These things have managed to blow me away. I know its not the best speaker out there, but for all the research i have done, these are still the best bang for buck, literally and figuratively. The bass these produce is quite staggering for the size, and with my apartment and the walls the sound resonates and creates a good vibration in the room, like its an actual sub. I have the Sony XB-31, and the XB-41, both with the lights, and i have been overall satisfied for a while with those. Sound great, but with these i have come to the realization that with the Sony, you are paying more for the all around experience of the speaker, and not just the sound quality. This I got on sale for 109, and the other one I ordered because I wanted the blue one. And as soon as I got the first one, it was almost a no brain decision to get another one for travels, and the pairing together to make that "stereo" sound. (Onyx Studio 4-2 tweeters, and 2 "subs") Onyx 5-1 bigger sub, and a single tweeter. None the less still amazing. I have not owned the 4, but videos on you tube should suffice to explain the difference in detail. There are some minor setbacks, but mostly nit picky things such as, no accurate indication for battery level, battery life (Spoiled by the XB-41 amazing battery life in my experience, 7 months) and the slight reduction on power output when not plugged into the wall (Understandable from an engineering, and design standpoint though). But overall, super premium feel, no cop out on materials, and the handle design has grown on me. The studio 6 is out now, with an water certification, not much content out yet, but from what I see, not much different, and sound is not as great. Strictly comparison speaking, because no matter what they still sound amazing, just doing in depth homework. I don't plan to use these as the throw everywhere, water, mountain adventure speakers, so the water should be fine without. These are worth the price. I would say.., there worth 200 if not more, most speakers in the class were looking at at those price points barely stack up. Still good, but just suited to different listeners/environments. Overall amazing, and I think unless your super picky about it, or over audiophile about everything and expect these to match home theater, and crazy headphone setups you will thoroughly enjoy them. I myself am not a scientist about it, but to average; a very picky chooser on sound quality. These satisfy with ease with little drawback. Not worth enough to mention though because nothing is perfect, and for what you get... Man, just try it yourself.