When you look back at how phones have progressed over the last few years, it's easy to just focus on the top models: your iPhones and Samsung Galaxy S-es. However, for your average person who wants a phone but doesn't want to blow a massive hole in their bank balance or sign up to a 2-year contract, the cheaper stuff has been more important.
Since 2013 the quality of affordable phones has skyrocketed. And the Oppo F1 is out to get you as close to a £500 phone experience as is possible for just £170.
And you know what? It gets pretty close. If the OnePlus X doesn't appeal then is the Oppo F1 in with a shout for pole position?
Oppo F1 review: Design
While the F1 doesn't quite manage to chip its way in under the £150 mark, it's still one of the nicest-looking phones you'll find at £170. It has a bit of an iPhone whiff to it, thanks to an ultra-slim 7.3mm frame and light champagne-gold aluminium back.
Looking from behind and it's a bit of a looker, isn't it? It's far slimmer than the Moto G, which actually costs the exact same cash in its 2GB RAM, 16GB storage version.
The Oppo doesn't stand up to ultra-close scrutiny like an iPhone 6S will, of course, but then there's only so much a company can do with this sort of budget. The F1's sides are actually plastic, as are the top and bottom sections of the rear. On the positive side, however, this side-steps any possible signal issues you can get with an all-metal phone, but does mean the flashy style is really a clever veneer.
The OnePlus X comes across as more convincingly "expensive" right down to its bones. Like that phone, the Oppo F1 uses non-lit soft keys, which some people find annoying. However, your fingers will soon bake the back button's position into muscle memory anyway. We haven't found it an issue.
READ: OnePlus X review
Of course, if you want fancy extras like a fingerprint scanner, you'll have to spend a bit more money on something like the Nexus 5X. While the Oppo F1 is a good-value phone, aside from the look it caters for the basics rather than such fancy extras.
These basic building blocks include things like having 16GB storage and a memory card slot. It even has dual-SIM support. Oppo is usually out to win a few nerdy fans, after all.
Oppo F1 review: Screen
Where the specs of the Oppo F1 start to sound a little ordinary is with the screen. It has, as some of you will have guessed, a 5-inch 720p IPS LCD screen. This is the grade of display that has been the budget standard for a while now.
It's enough to get you by; it's fairly sharp and large enough to, say, watch Netflix on - but it doesn't have quite the smoothness of the 1080p displays of the OnePlus X and Nexus 5X. It's one of the better reasons for considering spending a little bit more for one of the affordable 1080p phones.
The Oppo F1 still has a satisfying display, though. Its colours pop without looking oversaturated, it uses Gorilla Glass on top and goes pretty bright. For the first few days of our use the auto brightness setting seemed to be all over the place, but this seemed to settle on its own. The white balance is a little off too, with no way to change it, but your eyes bed in after a couple of days anyway.
There's a tiny 2.5D curvature to its edge too, which is carried on in the plastic screen surround to trick your mind into thinking the Oppo F1 is finely bevelled. Spoiler: it's not, the curves being largely cast in plastic.
Oppo F1 review: Software
Where the Oppo F1 starts heading into rockier territory is with its software. Like most other Oppo phones, it uses the ColorOS user interface rather than standard Android.
It's one of the more meddlesome interfaces, flattening Android by getting rid of the apps tray. This means you have to actually put a bit of effort in and arrange your apps, unless you want your phone to become an app icon junkyard.
Since Android 5.0, the default look of the system has been very curvy and friendly-looking, where ColorOS is a bit stiff and more angular. Oppo has tried to put some of the fluidity of the Google Now interface into ColorOS, but the look itself is a little dated.
After using the Oppo F1 for a week or so we tried switching over to the Google Now Launcher, which gets you the look and feel of a Nexus-style device through most of the phone. It is a big improvement, and probably how we'd recommend using this phone. ColorOS has themes that reskin the software pretty comprehensively, but unless you're willing to spend a while digging around in the Themes app library most will probably appear a downgrade.
ColorOS isn't awful, and doesn't introduce any major lag, but there's nothing much to justify its use other than it being a way to stamp more Oppo personality on the F1. One of its other unusual tricks is that one full home screen is given over to music controls. It's an odd move, right?
Oppo F1 review: Performance
Still, what matters most is that the F1 feels fast. Oppo has made sure of that with what are really pretty impressive specs for a 720p-resolution phone. It has a Snapdragon 616 CPU and 3GB RAM - which is loads for the price.
This is a lower-mid-range eight-core CPU, an awful lot like the Snadragpon 615 we've seen in mid-range phones for the last year or so, but clocked a little faster. For a 720p device it has more than enough power, and we've noticed almost no major performance or serious bug issues in the time we've been using the F1.
Some of the top-top phones are perhaps marginally nippier with app loads and app switching, but there's not a world-changing difference in it.
Oppo has really tried to squeeze the most out of the F1's budget rather than just thrown a new offcut rejects together. There's even some of this sense in the speaker, which goes pretty loud and doesn't sound weak like some cheaper phones. It's a little harder on the ear than some much more expensive models, but for a phone this thin, it's actually rather impressive. In terms of position and delivery, it's nothing special, though. The Oppo F1 has a single rear speaker, not a front stereo pair.
Oppo F1 review: Battery life
We had no issues with the Oppo F1 getting particularly hot, nor its battery draining down at an alarming rate either. The phone has a completely locked-in 2,500mAh battery, and it'll last you comfortably through a day.
We generally had between 10 per cent to 30 per cent charge left at the end of a day, depending on how hard we had been hammering the phone. Oppo clearly isn't out to set any standards or even get close to any existing ones. However, you do get the sense that planing the Oppo F1 down to its 7.3mm thickness hasn't resulted in the battery stamina being flat-out rubbish.
Common to just about every phone at this price, the Oppo F1 doesn't seem to have any sort of fast-charging abilities. It's the classic overnight charge that works best here.
Oppo F1 review: Camera
The F1 has an 8-megapixel selfie camera, using a 1/4-inch sensor. In the regular rear sensor world, that sort of size is nothing to brag about. But it's still a larger-than-average sensor for selfies.
The point of a bigger sensor? It means the Oppo F1 can make better use of that 8-megapixel resolution in less than perfect light, where a true bottom-rung sensor would end up turning everything to mush.
This is certainly one of the better selfie cameras you can get at the price. It can render fine detail in hair indoors, even if a reliance on processing to bring this out end up with the image looking a little scratchy viewed up-close. For the price you can't argue, though, particularly when it's also fast to shoot.
The rear camera is a bit closer to what we've come to expect at the price, after phones like the Moto G 3rd gen and OnePlus X started using good-quality sensors in sub-£200 phones last year. Oppo appears to have used the same (or similar) sensor as the OnePlus X: a Samsung ISOCELL 13-megapixel sensor paired with an f/2.2 lens.
It's a decent sensor that's also similar to the widely-used Sony IMX214 (seen in the latest Moto G) both technically and in terms of image quality. In daylight you can get some great shots, with good detail and fairly good dynamic range.
Despite offering phase-detection autofocus, actual shooting speed is decent rather than lightning-fast, but it's up there with the better performers at the price.
It's only when the light starts to dip that the Oppo F1 starts to falter a bit. The phone uses much less aggressive dark scene brightening techniques than the OnePlus X, resulting in some low-light images not looking so obviously soft. However, if the sensitivity is pushed in particularly low light scenes then it is a mush fest. It's not going to challenge the Galaxy S6 any time soon.
An obvious camera to compare is that of the Nexus 5X. Its giant 1/2.3-inch sensor is far better at retaining clarity in low-light shots, it's dynamic range and image noise handling are better in pretty much all conditions. The Oppo F1 is also a little slow at producing HDR images, with a clear (but not hair-pulling) decrease in shot-to-shot speed. But then the Nexus 5X is quite a bit more expensive.
There are some neat extra modes too. Ultra HD melds four exposures to create a massive 8320 x 6240 image, the equivalent of 51-megapixels. The idea that it really quadruples image detail is nonsense, of course, but the mode can help reduce fine image noise a little.
The Oppo F1's Animated GIF mode does what it says on the tin and is good fun, while the Slow Shutter mode lets you take exposures up to 16-seconds long. You'll need a tripod to make good use of this mode, but it'll let you take much more creative images.
There's more too. In the camera app you can switch on additional modes, including the full manual Expert mode, double exposure, Time Lapse, raw photo capture and more. These are the sorts of features we'd only really expect to see on Oppo's higher-end models.
The Oppo F1 is a neat phone, particularly if you're after something that'll keep you away from pricey contracts. It's a slim yet slick performer for the cash - one that doesn't reveal its affordable roots too quickly.
However, with just a 720p screen and ColorOS software you might be put off. If not then the only real remaining question is whether you're enough of a hardware veteran to make upgrading to a 1080p phone like the OnePlus X worthwhile.
Does the F1 achieve pole position in the budget phone rankings? Not quite, but the speedy performance is enough to keep it in contention.