I use the term "phone" loosely when describing the OnePlus One, because this sucker is clearly a phablet. It's 8 percent longer, 4 percent wider, and 10 percent thicker than the Galaxy S5. I'd say the One is past that threshold where some smartphone shoppers are going to find it a little too big.
The OnePlus One is also 12 percent heavier than the Galaxy S5. Though when you take the One's bigger surface area into account, the GS5 is actually a little denser.
OnePlus took an unconventional route in giving the One a magnesium finish. You'll also be able to buy replacement backs in even less conventional materials like bamboo, kevlar, and denim.
Samsung has been thinking a little out of the box lately as well, giving the Galaxy S5 a faux leather backing. This gives it a slightly soft-touch feel in hand.
These are the standard color options for each phone. At least at launch, OnePlus is tying the white model to the entry-level 16 GB One and the black model to the (US$50 more expensive) 64 GB edition.
If you can live with the One's enormous size, then the tradeoff is a 16 percent bigger screen.
The GS5 has a physical home button and capacitive back and recent apps keys below its screen, so you get to use its full screen for your apps and content. OnePlus, meanwhile, took customization to a new extreme by letting you choose between using its below-screen capacitive keys or virtual onscreen keys.
Display (resolution and pixel density)
Both phones have sharp 1080p displays. The GS5's screen is one of the best in the business, and I don't imagine the One's will give you anything to worry about either.
The Galaxy S5 has a swipe-style fingerprint scanner in its home button. You can use your print to unlock your otherwise passcode-protected phone.
Wake with voice
OnePlus was obviously paying attention to the Moto X when it added this feature. You can train the One to recognize your voice, and jump into a Google Now search even when it's asleep.
The GS5 has KitKat's hands-free Google Now voice control built-in, but it only works when your phone is on and you're on your home screen.
Heart rate monitor
As many a Samsung commercial is going to remind you over the next few months, the GS5 has a heart rate sensor on board. It sits next to its flash, right below its rear camera.
Taking a page from LG's book, the OnePlus lets you turn on its screen by double-tapping on the sleeping display.
If I had to pick one killer feature for the GS5, it would be its water resistance. It can sit in 1 meter (3.3 ft) of water for 30 minutes, and keep on ticking. We've seen this in other phones, but the Galaxy S5 is easily the highest-profile handset to shield itself from the elements.
Each handset has the speedy Qualcomm Snapdragon 801 processor inside. In both cases, performance is going to be top-notch.
The OnePlus One joins the Galaxy Note 3 as one of the few phones that can brag of having 3 GB of RAM. The GS5 has a more standard 2 GB.
Here's yet another unconventional move by OnePlus. Phone manufacturers almost always offer a 32 GB tier right above the base 16 GB, but OnePlus skips that and jumps straight to 64 GB. Best of all, that leap only costs you an extra $50.
The Galaxy S5's rear camera wins on resolution, and we found it to be pretty damn good in experience too. My biggest beef with the GS5's camera is that it's surprisingly slow to launch – especially for such a speedy phone. We haven't yet put the One's camera through the paces.
Dual LED flash
The One has a dual LED flash, which can help add a little more color and balance to those (often washed-out) flash photos. With that said, from using the GS5 for the last few weeks, I think Samsung might have thrown in some automatic software-based processing that meets a similar end.
Slow motion video
Both phones let you shoot video in slow motion, if you're into that sort of thing.
The One and GS5 both run Android 4.4 KitKat, packed with Google services, but that's where the similarities end. The One runs a variant of the modding community's darling, Cyanogenmod (this build is CM 11s). Like every mobile device from Samsung, the GS5 runs the love-it-or-hate-it TouchWiz UI.
Infrared (IR blaster)
It doesn't look like OnePlus put an IR blaster in the One. The infrared in the GS5 lets you use your phone as a remote control for your TV and cable or satellite box.
Like just about every other high-end Android phone from the last few years, both phones have NFC chips inside.
Based on our testing, the Galaxy S5's battery life will be hard to beat. But the One does hold a little more juice, for whatever that's worth.
Ultra Power Saving Mode
If your battery life does get low, then the GS5 has an innovative feature that lets you stretch the remaining juice out pretty far. Ultra Power Saving Mode turns your screen black & white and severely limits background processes, to give you an estimated extra 24 hours out of just 10 percent remaining battery life.
The Galaxy S5 launched earlier this month, while the One will make its way to customers sometime in the next three months.
Starting price (off-contract)
Which phone has the better blend of specs and features? Well, you could make a fair argument for either one. But pricing is where the One really stands out. Its $300 full retail starting price puts it in a league of its own. Of course many US customers buy their smartphones subsidized with a two-year agreement, but, at only $100 more off-contract than the GS5 typically costs on-contract, you can't deny that the One is shaping up to be one hell of an overall value.