The OnePlus One has plenty of promise, and it doesn't disappoint. For a non-contract, SIM-free price of $299 (around £180 or AU$320) for the 16GB version and $349 (roughly £210 or AU$380) for the 64GB model, the Android-powered smartphone is one of the best deals you can get today. It's a terrific price for a 4G phone, especially if you don't need the fancy features found on the $700 HTC One M8 or the $600 Samsung Galaxy S5 .

Yet there are some significant "buts" in this proposition. Getting your hands on a One is harder than you'd think. Ahead of a release that's set for sometime in June, OnePlus is selling the phone only via an odd invite system. Furthermore, you can buy it only on the OnePlus website, so you won't have the opportunity to get a test it in a shop. After-sale support is all online, too, which may be a problem given its rather unstable software. Furthermore, its 4G LTE works only on specific bands, meaning it may not function with your carrier.

All of these things make the One best for an experienced Android fan who wants as much freedom as the OS can bring -- and is willing to put in the effort to own it.

Still, in the highly competitive Chinese smartphone market, it could be that these low-cost marketing tactics will help OnePlus build awareness of its brand against heavyweights such as Xiaomi or Huawei. But at the end of day, it's the quality and performance of the One that will entice buyers, and fortunately, that's where this smartphone excels.

Design and specs

The design of the OnePlus One was instantly familiar, and after looking through my pictures of the Oppo Find 7 , it appears the phones are practically siblings -- only a few details such as the button layout and placement of the volume jack differ. That makes perfect sense, since OnePlus is part-owned by Oppo, and the One is made at Oppo's facilities.

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The 5.5-inch, full-HD display, which has a resolution of 1,920x1,080 pixels, is bright and vibrant and is usable even under bright sunlight at noon. Weighing in at 160g, the handset felt light despite its size. That said, I found it a little too wide to use with one hand -- a 5-inch display is still my ideal size for one-handed operation.

Like the Find 7, the OnePlus One sports a slightly curved top and bottom. The power button is located on the right side, while the volume rockers are located on the left. When I tested an earlier prototype, the slim buttons were pretty hard to press. While the review unit's rockers are shorter in length, they're actually more clickable and easier to work with.

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Instead of having the screen cover the entire front of the phone, the glass ends just slightly before the edges at the top and bottom. This exposes the silvery plastic below it, and I confess I'm not exactly fond of this design. It does catch the eye, but I have a feeling dirt is likely to accumulate at the edges, and it feels strange to touch, due to its having two edges instead of just one.

The OnePlus One has a soft-touch plastic rear, and it feels great. The curved edges mean nothing sharp digs into your palm when you're holding it, and the phone feels balanced and not the least bit unwieldy.

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There are three touch-sensitive buttons located below the screen, but you can disable these and use onscreen keys if you prefer. When turned off, you can't see the buttons except under bright sunlight.

Unfortunately, you don't get a lot of exterior choices on the smartphone. The 3,100mAh battery isn't removable, and there's no micro-SD card slot located underneath. As such, you have to choose between getting the 16GB model or the 64GB version. With the more capacious model only $50 more (most phonemakers put a much bigger markup on extra storage), it's clearly the better deal.

The One is powered by a 2.5GHz quad-core Qualcomm Snapdragon 801 processor and a generous 3GB of RAM, putting in the top tier of mobile power. More on that in the Performance section, below.

4G LTE

It has LTE support for some US (AT&T and T-Mobile) and UK networks (EE and Three), as well as some in Europe -- but not all. This is potentially a major downside, especially as you can't try it out before paying for it. My advice would be to look at this list of 4G LTE networks, see which band your carrier uses, and compare it to this list of bands the One supports: 1, 3, 4, 7, 17, 38, and 40.

It's not as though it won't be able to make calls if it doesn't support your network's band, but you won't get the benefit of the fast data speeds you're paying for. Besides 4G, it has quad-band 3G, NFC, Bluetooth, and dual-band Wi-Fi.

Software and features

The OnePlus One runs modders' favorite CyanogenMod 11S, which is based on Android KitKat 4.4. It's very similar to stock Android, but with a few modifications. These include an expanded desktop mode, and the ability to use gestures to turn on the camera or the LED light when the display is turned off. Other interesting tweaks include a voice-activated wake-up, and themes that let you really customise how the UI looks.