Introduction:

The Cases:

The Bezels:





The Dials:





The Lume:

The Bracelets:

The Movements:

Final Thoughts:

At first, it may seem more than a little counter-intuitive to compare these two watches. After all, there is quite a serious price differential between them - one retails for ~$2,500, while the other retails for ~$4,400. Of course there will be significant differences between them. How comparable can they possibly be?In my personal opinion, they are quite similar. In some ways, I find the Pelagos to be the long lost Swiss sibling of the MM300, so to speak. Allow me to elaborate:* Both watches have serious roots in their companies respective histories; the Pelagos in the Tudor Snowflake, and the MM300 in Seiko's iconic 6159.* Both watches are absolute freaks in the lume department, among the best on the market today.* Both are no nonsense, unapologetic saturation divers.* Both have unique, on the fly adjustable clasp systems on the bracelets (and both come with a rubber strap).* Both contain fully in house movements, and are made by the worlds only two completely vertically integrated watch manufacturers - the Rolex and Seiko groups.And yet on the other hand, they are different enough that there is plenty to compare:* The Seiko has a heavy steel case and a light titanium clasp, while the Tudor has a titanium case and a steel clasp.* The Seiko is quite shiny, while the Tudor is matte.* The case of the Seiko is beautifully sculpted, while the Tudor is apologetically utilitarian in form.And so much more. So, let us dig in to the meat of this review:MarineMaster 300:The Seiko MarineMaster 300 uses 316L stainless steel, treated with Seiko's proprietary Diashield coating. In my first hand experience, this coating is extremely effective in preventing desk diving swirlies and other daily scratches. After four months of ownership, there is hardly a blemish to be found.One consequence of the choice of material is that the case is extremely substantial, it weighs in, with the bracelet, at approximately 210 grams.Yet despite being rather chunky, the MM300 case is a thing of beauty to behold. The sides of the case feature sharply beveled and beautifully polished edges that meet in the center to form a brushed plane. The effect in person is striking, giving the case a quite intense character. The practical effect of this sculpted case is that it makes the MM300 wear several millimeters smaller than its on-paper 44mm case would suggest. The case of the MarineMaster is also unique in that it features monobloc construction - that is, there is no removable caseback to be found. I find this to be both interesting and desirable, as it is one less possible point of leakage.The MarineMaster is, as previously mentioned, a saturation diver. It achieves this in a rather nontraditional way, without a helium escape valve. In exchange, the MM300 simply relies on seals that are so good, they prevent Helium from entering the watch in the first place. Neat!I do however, have some minor quibbles with the MM300 case. The first is that the crown stem feels rather flimsy. I have more difficulty screwing and unscrewing the crown than I do in my other dive watches - I feel the need to be delicate with it. And the second, is that the metalwork on the caseback is not as nice as on the sides or the front. The various angles on the caseback appear more stamped than sculpted, which is a disappointment compared to the sides of the case. The traditional Seiko tsunami motif could be more detailed as well.Score: 8/10Tudor Pelagos:The Tudor on the other hand, is made of grade 2 titanium. While grade 2 titanium is much easier to scratch than stainless steel (much less diashield coated stainless steel) I appreciate the use of this material. The Seiko can be a very heavy at times, whereas the Tudor always feels perfectly at home on my wrist. It is certainly a much more comfortable material.The case of the Tudor is vastly more utilitarian in form than the MM300. One consequence of the use of grade 2 titanium, of course, is an inability to alternate finishing between brushed and polished. With that said, the Tudor case is expertly crafted. The upper edges of the case are very smartly beveled, and the crown guards meet to form a perfect pointed edge.The Tudor as well, is a saturation diver. It takes a much more traditional approach, with a Helium Escape Valve located at 9:00 on the case.Like the MM300, I do have several minor quibbles with the Pelagos case. Firstly, although I know that Tudor, as part of the Rolex group, traditionally does not decorate their casebacks, it is not very interesting to look at. Finally, the quality of construction is almost too precise on the Pelagos. There are a number of sharp edges and corners to be found, which can be slightly uncomfortable.Score: 7/10MarineMaster 300:The Marinemaster 300 has, in my humble opinion, one of the most interesting bezels found on a modern dive watch. To my understanding, it is made of some kind of lacquer applied directly onto the steel bezel (that is to say, there is no bezel insert). The result, while delicate (and expensive to replace), is absolutely stunning. The way it catches the light is dazzling. Although I often see it compared to ceramic bezels in the way it plays with the light. Although I agree, I have also found that the bezel on the MM300 has an additional dimension that Ceramic bezels do not. When viewed at certain angles, it almost takes on the appearance of the "ghost bezels" we see on vintage rolexes.The operation of the 120 click MM300 bezel is extremely precise. When turning it, it feels almost I am turning the heavy dial to a bank vault. With that said, I have found that the operation of the MM300 bezel depends on whether it is wet or not. If the bezel mechanism is wet, it becomes much lighter and easier to spin.Score: 4/5Tudor Pelagos:I find the bezel on the Pelagos to be possibly even more compelling. While the matte blue ceramic is not as pretty or as eye catching as the MM300, the lumed ceramic is beyond extraordinary, both in practicality and in beauty. I will touch more on the lume later in my review, but in my opinion this lumed bezel insert makes this watch absolutely sing. The scratch resistance as well just has me singing praises.In operation, the 60 click Pelagos bezel, like everything else on this watch, is surgical in its precision. There is absolutely no play between clicks, and its operation is not dependent on whether or not the bezel mechanism is wet or not; its behavior is always predictable. I find absolutely no way to fault this bezel.Score: 5/5:MarineMaster 300:The dial of the MarineMaster 300 is really something to behold. For such a simple watch, there is a lot going on. The dial is set extremely deep into the case, under a very thickly domed hardlex crystal. In combination with the raised flange around the dial, it creates a great sense of depth that I have seen in few other watches.When looking closer at the dial, you begin to notice numerous tiny yet significant details. Each lume plot, for example, has very clearly been hand painted, producing all sorts of wonderful texture on the lume. The hands have been intricately brushed on the surface, and then beveled and polished on the edges. The date wheel, rather than being the traditional white, is actually a finely brushed steel. The combination of all of these minor details results in a genuinely, genuinely stunning dial.My only gripe is that I wish that the lantern seconds hand were finished with the same delicacy and care that the hour and minute hands were. I also wish the hardlex crystal were sapphire.Score: 9/10Tudor Pelagos:The dial of the Pelagos, like the MarineMaster, also has a flange to increase perception of depth. This, in my opinion, was a really smart move because even with it the Pelagos dial can look a little bit flat. With that said, I think the Pelagos finds a really happy medium between depth and flatness that really, really works and provides for an extremely legible and interesting timepiece.The dial of the Pelagos, like the rest of the watch, benefits from absolutely surgical precision. Lume application, printed text, and even color matching are all absolutely perfect. The extent to which the designers of the Pelagos were concerned about cohesive design really shows through in a number of ways in the dial. The relationship between the square hour indices and the snowflake hands for example, or the fact that the dial and watch hand pinion are perfectly color matched with the ceramic bezel.Much like the bezel, I find nothing to complain about with regards to the Pelagos dial. With that said, it does not have quite the same complexity in my eyes as the MarineMaster 300 dial.Score: 8/10I wanted to designate a section completely to luminescence, and it is what initially got me interested in these two watches. They are both absolute freaks in the lume department.MarineMaster 300:This particular MM300 is the most recent, SBDX017 model. The significance of that, when it comes to lume, is that it used Seikos newest lumibrite formula. Seiko claims it to be 60% brighter than their previous formula, and I have found this to be true when compared to my Monster. The lume on this watch is so incredibly bright that it actually glows in broad daylight. If you step into even the slightest shadow, it will flash up like it is taunting other less generously endowed watches. In the dark, it could nearly function as a makeshift flashlight in a pinch. This lume is the standard green found in Seiko's lumibrite and most Superluminova formulas.Score: 5/5Tudor Pelagos:The Pelagos, while not nearly as bright in the lume department as the MarineMaster 300 (I would estimate it's about 75% as bright), has a number of things going for it. The first is that delicious, delicious lumed bezel. While the MM300 can be mistaken for any of a hundred other dive watches in the dark, the Pelagos is very distinctly a Pelagos. It is very much the same watch that it is with the lights on, and I absolutely love that. It also uses Rolexes unique Chromalight formula which takes on this magical blue hue. While the MM300 is certainly brighter, I would venture to say the collective lume impact of the Pelagos is higher because of the lumed bezel and the unique color.Score: 5/5MarineMaster 300:The bracelet and clasp, unfortunately, is an area where I think the MM300 really struggles to keep up with the Tudor. While I often see it claimed that the MM300 has a "faux 5 link bracelet", this is not true. If you look at it from the front side and jiggle the bracelet around, you will see gaps between the various links moving around. My understanding of the construction of this bracelet is that there is a solid outer link, and a hollow, folded inner link. Thus, the cheap feeling that many people experience from this bracelet. Not the best.The clasp is a confusing beast. On one hand, it has absolutely spoiled me - I can't stand wearing any bracelet that does not allow for on the fly micro adjustments anymore. And yet, the execution and build quality is not there. It is constructed from the same kind of stamped material that you would find on the bracelet of a Seiko Monster, which is a mere fraction of the price. Further, when the micro adjustment is extended, it creates a rather jarring visual. The micro adjustment also has a tendency to dig into my wrist when it is extended. The end links also have a fair bit of play against the case. At least, with the drilled lug holes, this allows for bracelets and straps to be fairly easy to change. I also do not appreciate the pin and collar system.I really have a love hate relationship with this bracelet, and I with is was better executed.* The watch also comes with a generic rubber strap, which I find to be too stiff and rather uncomfortable.Score: 5/10Tudor Pelagos:The bracelet on the Pelagos on the other hand, is masterfully designed and crafted with the same surgical precision as the rest of the watch. The end links fit perfectly against the case, with no play whatsoever, The bracelet uses screws to hold the links together, rather than pin and collars, and the clasp is precision machined rather than stamped. Interestingly, the clasp seems to use some kind of ceramic ball bearing rather than simple friction to click shut.The clasp on this is what I wish the MM300 clasp would be. It allows for on the fly adjustment, and there is no visual break in the bracelet even when fully extended. Further, the springloaded auto adjustment system is really a stroke of genius. I can just set it and forget it, and the watch will conform to my wrist.The skeletonized parts on the inside of the clasp form the shape of the tudor shield, which is a nice touch.* The watch also comes with a rubber strap custom made for the pelagos and a rubber divers extension. The buckle takes the shape of a Tudor crown, which is a nice touch. These rubber straps ooze of the same quality as the rest of the watch.Score: 10/10MarineMaster 300:The MM300 utilizes a base Grand Seiko movement, the 8L35. This is the same movement as the Grand Seiko 9S55, but unregulated. I often see it claimed that the 8L35 is "undecorated" but this is not true, as evidenced by the photos. It is simply not decorated to quite the same level as its 9S55 counterpart. This movement utilizes 26 jewels, has a nice 50 hour power reserve, and utilizes Seiko's MEMs manufacturing technology to create a skeletonized escapement. It is rated to -10, +15 seconds per day, but my example has gained a consistent 2 seconds per day since it was purchased.Score: 8/10Tudor Pelagos:The Pelagos utilizes Tudor's first in house movement, the Tudor MT5612. This is a "next gen" movement that makes use of a free sprung, variable inertia balance with a silicon hairspring. It has a fairly utilitarian finish as Rolex made/designed movements tend to have, a instant date change function, and a fantastic 70 hour power reserve. What this means is that you could take the watch off on a friday, and it will still be ticking away happily on monday morning. It is COSC Chronometer rated at -4, +6 seconds a day. My particular example is keeping time dead on, as of yet.Score: 10/10I absolutely adore both of these watches, and am glad that I have both in my collection. The Tudor is by far and away, IMO, the technically better watch. It is more comfortable, it has a far better bracelet, and a much more advanced movement. On a day to day basis, this will be the watch that is on my wrist. The Seiko on the other hand, while it does have its quirks, its faults, and its shortcomings, is really a spectacular watch with a ton of character. There is really nothing else like it on the market, and when I strap it to my wrist, it feels genuinely special. The only thing preventing it from being my daily wear is the weight. My god, the weight. My wrists were not built for that.Final Scores:MarineMaster 300: 39/50 = 78/100Tudor Pelagos: 45/50 = 90/100I hope you appreciated my rather long winded review. I really, really love both of these pieces, and was looking for a comparative review when I was cross shopping them. Also, I apologize for the picture quality - photography is not my strong suit. (And the sideways photos, I don't know why they are uploading like that).(Movement photos shamelessly stolen from the web).