Korean electronics giants Samsung and LG compete in just about every area in which they operate. In the smartphone space, though, Samsung's Android-powered lineup remains top dog. Not only is it the world's top handset manufacturer, but it's Galaxy range, headed by the Galaxy S5, also represents the most familiar face of Android in the eyes of consumers. LG has had a comparatively shaky start in the smartphone world, but in past week it's finally brought its most compelling handset yet, the LG G3, to the U.S. market. With eye-catching specs like a 5.5-inch "quad HD" display and an impressive optically-stabilized camera, the LG G3 represents one of the more credible challengers to the incumbent Samsung. But the GS5 itself is Samsung's strongest flagship yet — the manufacturer's first proper water-resistant flagship, with a built-in heart rate monitor and biometric security to boot. We've had both devices in our hands for some time now, so it's time to put them head to head and see how they compare. Verizon is offering the Pixel 4a for just $10/mo on new Unlimited lines

Look and feel Two plastic phones, but vastly different designs. These two are both traditional plastic smartphones with removable back panels, and chassis dominated by their large displays. But despite the use of similar materials, there are plenty of areas of contrast. The G3 sports a rounded exterior with extremely thin bezels and a "metallic" textured back — read: plastic with a fancy coating — while the GS5 has a more squared-off design with reflective accents. There's a size difference, of course, given the gulf in the two devices' display dimensions, but the larger LG handset really isn't a whole lot bigger in real terms than Samsung's offering. That's mainly down to the G3's narrower bezels, which allow for a greater proportion of the front face to be taken up by the 5.5-inch display. The in-hand feel is vastly different too. The G3 is the slicker of the two, thanks to the unique texture of its back panel — glossy, but somehow not slimy or fingerprint-laden — while the Galaxy S5 has a matte plastic coating. (Go with the black GS5 and you'll get a soft-touch battery door; the other colors get a more traditional textured plastic finish.) With its smaller size, flatter back panel and grippier rear, the GS5 is perhaps the easier phone to one-hand, but the G3 is remarkably hand-friendly for a 5.5-inch phone.

The G3 also wins points for its novel rear-mounted buttons, putting the power key and volume rocker within reach of your index finger at all times. That said, the GS5's more traditional side-mounted buttons do the job just fine. Around the back, the GS5's 16-megapixel camera module protrudes slightly through the back panel, while the G3's 13-megapixel shooter sits flush with the battery door. When it comes to the main buttons used to operate the phone, LG opts for the increasingly popular on-screen controls, while Samsung's sticking with its big clicky home button, flanked by capacitive back and task-switching keys. Generally speaking, we prefer the consistency of LG's approach, but we've had no trouble adapting to Samsung's button layout, and there's something to be said for being able to quickly wake the phone with a single press of the home key. Aesthetically, it's mostly a matter of personal taste. Neither phone will blow you away with premium materials like the HTC One M8 or Sony Xperia Z2. Instead, it's a question of whether you prefer the softer back and more squarish proportions of the Samsung device, or LG's curved, shiny derriere.

Hardware and performance Like most high-end Android phones released this year, LG and Samsung's 2014 flagships run Qualcomm Snapdragon 801 processors. Both phones use the fastest 2.5GHz variant — MSM8974AC if you want to get technical — with 16 or 32GB of internal storage. Samsung's coupled its CPU with 2GB of RAM across the board, but with LG your RAM size will depend on which model you pick up. G3s with 32GB of internal storage will get 3GB of RAM, while the 16GB variant comes paired with 2GB. We've tested both flavors of G3 and haven't found any massive performance delta between the two. Nevertheless, the 3GB model should have the upper hand when it comes to memory-intensive apps, and it's a shame it's not widely available in some part of Europe.

Elsewhere you'll get removable batteries and removable storage in both devices. microSD cards up to 128GB are supported, while there's a 200mAh difference in battery capacity — 2800mAh in the GS5, 3000mAh for the G3. Given that the G3 has to power a much higher resolution display than the GS5 with only a slightly beefier battery, you might expect longevity to have suffered in the LG device, but in our experience that's not quite the case. Both handsets have managed to get us through a full day of moderate-to-heavy use, racking up between 14 and 16 hours between charge. But the G3 frequently came out on top in terms of screen-on time, averaging a little over four hours compared to three on the GS5. Certain G3 models, particularly those sold in Europe, support Qi wireless charging out of the box. In other territories like Korea and the U.S., you'll need to buy a replacement back panel to charge wirelessly. On the Samsung side, a replacement Qi-compatible back panel is widely available, though this does add a little bulk to the device. Category Samsung Galaxy S5 LG G3 Dimensions 142 x 72.5 x 8.1 mm 146.3 x 74.6 x 8.9 mm Weight 145g 149g Colors White, Black, Gold, Blue Black, White, Gold, Pink, Purple Display 5.1-inch 1080p SuperAMOLED 5.5-inch QHD (2560x1440) IPS LCD CPU Qualcomm Snapdragon 801, 2.5GHz Qualcomm Snapdragon 801, 2.5GHz Platform Android 4.4 with TouchWiz Android 4.4 with LG UI Internal Storage 16/32GB + microSD up to 128GB 16/32GB + microSD up to 128GB RAM 2GB 2-3GB Cameras Rear: 16-megapixel ISOCELL rear camera, 2MP front-facing camera 13-megapixel BSI OIS+ camera, 2.1MP front-facing camera Value-added features IP67 Dust and Water Resistant, Fingerprint Scanner, Heart Rate Monitor KnockOn, Knock Code, Smart Notice, Smart Bulletin, Laser Autofocus Battery 2,800mAh removable 3,000mAh removable Raw performance is difficult to quantify, as it's impacted by touch responsiveness and animation speed as much as pure hardware muscle. However the Galaxy S5 has a slight edge in some areas. The fact that it's pushing fewer pixels through the same hardware gives it an advantage in graphically-intensive games, producing higher frame rates than the G3 in testing. What's more, the various UI animations seem a touch faster on Samsung's device. The LG G3 is no slouch, but unfortunately it is more prone to dropping frames in certain animations, particularly in the stock launcher. Both devices are as fast as any high-end Android phone in day-to-day use, but the GS5 feels slightly smoother than the G3 in doing so. The G3 wins on pixel density, but SuperAMOLED delivers brighter colors. The LG G3 scores a clear win on pixel density with its 2560x1440-resolution panel, boasting a ridiculous 538 pixels per inch. As we said in our G3 review, though, the device's main strength is its screen size, not its resolution. Being able to carry around a 5.5-inch display in a smartphone that's barely any bigger than the 5-inch competition is a big deal, and one that makes rivals seem decidedly poxy. But despite its ample size and pixel density, the G3 can't match the color quality of the Galaxy S5, appearing slightly washed out by comparison. While regular apps and web pages look great on either display, photos and videos will be best served by Samsung's 1080p SuperAMOLED panel. In our Galaxy S5 review we also praised the daylight visibility of Samsung's latest display, which is easier to see in direct sunlight than any previous AMOLED effort. That said, the G3 is also a strong performer in this area, and we've had no trouble using that 5.5-inch display in bright sunshine.

Software and features Here's where things really get interesting. Both the LG G3 and Samsung Galaxy S5 have a unique array of hardware and software features. On the Galaxy S5 you'll find IP67-rated water and dust resistance capabilities, meaning you're able to use the device worry-free around water. (At least if you first remember to close the plastic flap around the microUSB port.) Depending on how and where you use your phone, that could be a big deal. The GS5's other two stand-out features offer niche appeal. There's a heart rate monitor around the back of the device, below the camera lens, which works with the built-in S Health app to record and track your pulse. And a fingerprint scanner built into the home button adds biometric security for PayPal purchases, private, ahem, pictures, and your lock screen. Both are easy to ignore if they're not your cup of tea, but the fingerprint scanner in particular can be tricky to use with one hand, negating some of its usefulness for lock screen security.

Over on the G3, LG has its own proprietary lock screen features. KnockOn allows user to unlock their phone by double-tapping on the screen, while KnockCode expands this by securing devices with a specific pattern of taps. Other staple G3 features include Smart Notice — a widget that keeps you up to speed on future weather conditions (expect to be frequently told to take an umbrella), reminds you to follow up on missed calls and add new contacts to your address book. It's a nice idea, but it's far from indispensible. Google Now is by far a better implementation of this idea. Similarly, we can take or leave Smart Bulletin, the slide-out panel that incorporates an area for LG's very basic Health app, and a lower section for guiding you through features of the phone you might not be using. Most of the time it's inoffensive enough, but like Samsung's half-baked "My Magazine" pane on the GS5, we eventually ended up turning it off.

Between S Note, QMemo, Smart Stay, Smart Screen, Multi window and Dual Window, there's a lot of feature crossover. When it comes to basic software features, there's actually a lot of crossover between the LG and Samsung software experiences. Samsung has Multi window for splitting the screen between two apps, LG has Dual window. Samsung has Smart Stay, which keeps the screen on when you're looking at it, using the front-facing camera to see where you are. LG's Smart Screen does exactly the same. Samsung has S Note, LG has QMemo. S Voice. Voice Mate. You get the idea. Software design has been getting flatter over the past year, and this trend is reflected in the latest Android interfaces from Samsung and LG. LG tends to keep its things more subdued than Samsung, however, with fewer primary colors and a focus on basic icons constructed from geometric shapes. In our opinion the G3 has the classier UI, although overall we still prefer the look of stock Android HTC Sense. That said, Samsung finally seems to be making some meaningful changes to its TouchWiz UI and eliminating some of the visual and feature-based clutter.

Camera The LG G3 and Samsung Galaxy S5 pack 13- and 16-megapixel cameras respectively, but as usual the megapixel count alone doesn't tell the whole story. Samsung's camera uses ISOCELL technology, which is designed to reduce interference between individual pixels, along with new, faster phase detection autofocus. Meanwhile LG's rear camera can boast hardware stabilization thanks to the company's OIS+ technology, which helps to reduce blurring from hand motion, and helps out with low-light performance. So how do the two stack up in real-world use? Well, the Samsung Galaxy S5 is pretty much unrivaled when it comes to daylight performance. We've shot some of the best daytime photos we've ever taken on a smartphone using the GS5, and thanks to its excellent HDR mode it's easy to take clear, vibrant pictures even in backlit or very bright conditions. Where the GS5 doesn't shine so brightly, however, is in low light. To avoid producing grainy, noisy images you'll need to use the software stabilization mode, which waits — often for several seconds — until things are stable before taking a shot. Even then, night-time shots often look smudgy and blotchy as software-based noise reduction runs roughshod over any fine detail.