Are you looking for a smartphone that's all power on the inside, with sexy good looks on the outside? Well, then it's going to be hard to beat these two. Join Gizmag, as we take a hands-on look at two phones that have beauty and brains, the HTC One (M8) and Apple iPhone 5s.

We've had both of these phones in-house for a while, and have a few thoughts to add to our specs breakdown from back in April. It's one thing to look at hardware and features, drawing conclusions about what you might expect. But what's it like to actually use the dang things for at least a couple of months?

Well, the first thing you'll notice is a huge size difference. Apple will likely launch a bigger iPhone later this year, but, for right now, the One M8 is a much bigger phone. To be exact, the HTC One (M8) is 18 percent longer, 20 percent wider and 24 percent thicker (okay, so maybe we won't leave those specs completely behind).

On an experience level, that breaks down to a phone that easily slips into the meat of your hand (iPhone) vs. one that makes its presence felt a bit more in your hand or pocket. As we say every time we compare large and small phones, the iPhone's advantage is that it feels extremely light in hand (it's 30 percent lighter) and practically disappears in your pocket. The One's advantage is that its screen gives you a much larger window into your apps and media.

To be precise, the iPhone only gives you 64 percent as much screen real estate as the One M8. Let's say there are two properties for sale: one of them has one acre of land, the other has less than 7/10 of an acre. If the quality of land is similar and they cost the same price, you'd probably go with the full acre, right?

Of course you don't put tracts of land in your pocket or hold them in your hand, so this isn't a perfect metaphor. But if you were looking at screen size in a vacuum, then that's the difference that this would boil down to. The experience of using the One M8 is a bit closer to what you'd expect from a tablet, while the iPhone makes it impossible to forget that you're using an ultra-portable, ultra-pocketable phone.

Both screens are sharp. The One M8 is sharper, and if you set both phones side-by-side, you'll notice a little bit of a pixel density difference (the One packs 35 percent extra pixels into each inch). But I don't think this is big enough of a difference to base your decision on. You won't find any distracting pixelation of text or images on either phone.

If we take a step back from the phones' sizes and screens, and look only at their constructions, then we're going to see two absolute stunners. Both phones have aluminum unibody designs. I don't know if smartphones can be considered jewelry or not, but these two handsets make the best argument I've seen. The iPhone has a familiar look, with chamfered edges and a flat, dual-colored back. The One has a single-toned finish, with a more sloped backside (the gun metal color we handled is quite the looker).

We love the look and feel of HTC's One line, but if you wanted to play devil's advocate, you could argue that a phone like the One is riding the coattails of products that Apple made years ago. Apple's designers pioneered the trend of unibody tech products chiseled from a single piece of aluminum, like the groundbreaking MacBook Air in 2008, the iPad in 2010 and the iPhone 5 in 2012.

The One M8 is a gorgeous and brilliant device in its own right, and that's probably all that matters. I only make the point because I wouldn't necessarily call its design "innovative." HTC is standing on the shoulders of giants, putting its own spin on something that Apple already proved could be successful.

I don't think battery life is a concern in either phone, as I've never had a problem with either handset making it through a full day. In our standard test, where we stream video over Wi-Fi with brightness set at 75 percent, the One M8 lasted 49 percent longer than the iPhone did. The One does have excellent battery life, but I think this is also an example of why we take these kinds of benchmarks with a few grains of salt. On a typical day, I've never had to worry about either phone conking out.

The One M8 does have a very cool power-saving feature that could have very well been ripped off from Samsung (it was announced a month after a strikingly similar feature was announced for the Galaxy S5). Extreme Power Saving Mode, which is still rolling out to some carrier's versions of the One M8, lets you keep your phone up and running in a pinch. If your One's battery life drops below a certain (customizable) level, its UI will shift to a barebones, nearly black & white home screen. You'll be limited to basic functions like phone, mail and messages.

So what's the advantage of Extreme Power Saving Mode turning your One into the world's most expensive feature phone? Well, it can take just a smidge of remaining juice and turn it into hours of extra battery life. If you have a day when you use your phone longer than usual, EPS Mode can keep you from completely dropping off the grid. The iPhone has no equivalent feature.

Like Siri in the iPhone 4s, the iPhone 5s' killer feature is probably going to be standard fare in every new iOS device from now on. The 5s' Touch ID fingerprint sensor lets you set up passcode security for your phone, and then use your unique fingerprint to bypass it. It works well, you can program up to five fingers (including the same one multiple times to increase accuracy) and makes for a brilliant combination of security and convenience.

Later this year, when iOS 8 launches, Apple will open up Touch ID to third-party apps. This could be especially useful for banking and payment apps, as well as password storage apps like 1Password, LastPass or Dashlane.

The One M8 doesn't have any biometric sensors, but it does still have a few sensors onboard. These sensors are tied to features that are collectively called Motion Launch: a series of gesture-based shortcuts for some of the phone's most-frequented hotspots. So if, say, you want to unlock your phone, there's no need to mash the power button before swiping across the screen. Just hold the phone in portrait mode and swipe up on the screen. Or if you just want to check on notifications, double-tap on the screen to see your lock screen. Tap twice again to turn it back off. There are also Motion Launch shortcuts for firing up the camera, BlinkFeed (HTC's social and news feed widget) and your other home screen widgets.

I wouldn't call Motion Launch revolutionary. If given the choice, I'd take the security and convenience of Touch ID over the split seconds of time you'll save with Motion Launch. But it is still a handy set of features that can shorten the distance (by just a hair) between a sleeping phone and whatever you want to do with it.

I've never bought one smartphone over another because of its speakers, and I doubt you have either. But if I did, then my choice would be easy: the One M8 has the best damn speakers I've heard out of any phone. They're loud, full and – best of all – front-facing. Last year's One M7 raised the bar for smartphone audio, and the One M8's BoomSound speakers push that bar up even higher.

When comparing high-end phones these days, I find the quality of most of their cameras to be in the same general ballpark. A few unique features here, a couple of gimmicks there, but most of them aren't all that different. But the One M8 marches to the beat of its own drummer, with a very low resolution sensor that (sort of) redeems itself with the size of its pixels.

Like 2013's One M7, the One M8's camera uses what HTC calls "UltraPixels." Even though it only shoots in a mediocre 4 MP resolution, its pixels are bigger, which helps to makes it better at low-light photography. I find the One's low-light shots to be brighter and more colorful than those of most other phones, including the iPhone. The One's 4 MP shots won't look as sharp, though, and this will really show if you try to zoom in, crop or blow images up to poster size.

Both phones' cameras have dual-LED flashes, which can make flash shots look less blown-out and whitewashed, more colorful and evenly-lit.

The most unique thing about the One's rear camera is the little friend sitting next to it. See, the One M8 has a second rear camera that's devoted entirely to sensing depth. This opens the door to some gimmicky features that I'd never use, including a faux 3D effect (it lets you tilt your phone back and forth to see images from slightly different angles) and others that cartoonize or add a radial blur to the background. I could have done without most of those.

But there is one cool feature made possible by the One M8's depth sensor. UFocus simulates the blurred-background (bokeh) effect that you'd get from a DSLR with a wide-aperture lens. It isn't perfect, as it will sometimes pick up jagged little pieces of the background that it thinks are foreground (completely ruining the effect). But when it's on – and I'd say it's on about 60-70 percent of the time – it's a very cool feature. The One's dual camera setup could almost be written off as a cheap gimmick, but I'd say UFocus works well enough to justify the hardware.

Here's one example of UFocus working pretty well:

If all you're looking for is a straightforward camera that takes great shots with a simple interface, then I'd cast my vote for the higher-resolution iPhone. But if things like background blur and brighter low-lit shots are your priority, then the One's camera has a pretty unique bag of tricks.

We used to focus a lot more on performance in smartphones, running benchmarks and sweating minor differences. But that was back when most phones were as slow as molasses, and every little speed boost in the latest new model was like a breath of fresh air. Today, the performance of just about every high-end smartphone is way past the point of concern – including these two. Most mobile apps require very little in the way of processing power anyway, so, if anything, it's now the apps that are catching up to the hardware.

The One M8 and iPhone 5s are two terrific smartphones, and I wouldn't hesitate to recommend either of them to anyone. Obviously fans of Android and bigger screens will gravitate towards HTC's offering, while happy inhabitants of Apple's walled garden, and the end-to-end simplicity that goes along with it, will appreciate the iPhone.

Maybe the biggest thing to keep in mind here is that the iPhone 5s is moving closer to the end of its initial life cycle. Sometime around September, Apple will likely announce a new model, which is rumored to have a bigger screen (4.7 inches, with a 5.5-in model possibly following hot on its heels). So if you prefer everything about the iPhone except for its screen size, then you might ask yourself if you can hold off for three more months.

For a bit more on each phone, you can check out our individual reviews of the iPhone 5s and HTC One (M8). And if you want to cast your net a bit wider, you can check out our 2014 Smartphone Comparison Guide.