For the last couple of years, OnePlus has been aggressively pushing itself as the flagship killer - with phones offering top specs but often hundreds cheaper than the nearest rival. That much is true of the OnePlus 6T.

That position has slowly changed as the likes of Huawei sub-brand Honor has positioned itself as an alternative, and other Chinese brands are lining up for the takedown. The latest arrival in Europe, and the UK specifically is Xiaomi with the Mi 8 Pro

But which of these phones should you buy?

High quality designs

  • Xiaomi: Aluminium and Gorilla Glass 5, 154.9 x 74.8 x 7.6mm, 177g
  • OnePlus: Aluminium and Gorilla Glass 6, 157.5 x 74.8 x 8.2mm, 185g

Both handsets offer flagship-level quality, with an aluminium core meeting glass front and rear panels. OnePlus is typically sombre with a black finish (although other colours may follow), while Xiaomi has opted for a transparent back on the Mi 8 Pro for added geek appeal. 

The difference in size in these handsets comes down to display size as both are fairly bezel free and the thickness and weight comes down to battery, which is bigger in the OnePus. Between the two, OnePlus' display perhaps looks a little more advanced with the dewdrop notch, but we have to say we like the transparent back from Xiaomi - it's different and it stands out, while the OnePlus might just look like any other OnePlus. 

Display

  • Xiaomi: 6.21-inch AMOLED, 19:9 aspect, 2248 x 1080, 402ppi
  • OnePlus: 6.41-inch AMOLED, 20:9 aspect, 2340 x 1080, 402ppi

People like AMOLED displays and both these phones use AMOLED to great effect. The big difference here is in notch design. Xiaomi has a wide notch at the top, whereas OnePlus has evolved beyond that arrangement, reducing it to a pimple. 

It's this change in design that really lets OnePlus dominate the front of the phone and while both these displays are 1080p, OnePlus gives you a few more lines at the top. It's a slightly larger display overall, but the pixel density comes out the same. 

What does that mean? It means both are equally capable at displaying detail. In reality, there's technically very little to choose between to the two - it's mostly about the notch design. 

Both also offer an in-display fingerprint scanner. About the only difference is that Xiaomi's is pressure sensitive - but otherwise they work in the same way. 

Hardware

  • Xiaomi: Qualcomm Snapdragon 845, 8GB RAM, 128GB storage, 3000mAh battery
  • OnePlus: Qualcomm Snapdragon 845, 6GB RAM, 128GB storage, 3700mAh battery

Again there's parity with both phones sitting on the Qualcomm Snapdragon 845. It's insane that other phones on this hardware cost a third more, but there you go - that's what these phones offer. 

When it comes to RAM, Xiaomi is generous with 8GB; OnePlus has 6GB at the same price, with the option to step up to 8GB and 256GB storage for a little more. On balance for the extra storage that might be worth it - neither has microSD - but for value for money, Xiaomi comes out top. 

However, OnePlus has a bigger battery and offers better stamina. If endurance is your thing, you'll probably choose the OnePlus 6T as it will last longer and this makes a big difference in the battle between these two phones.

Cameras

  • Xiaomi: Rear 12MP, 1.4µm, f/1.8, OIS; 12MP, 1.0µm f/2.4 zoom; Front 20MP, f/2.0
  • OnePlus: Rear 16MP, 1.22µm, f/1.7, OIS; 20MP, 1.0µm, f/1.7; Front 16MP, 1.0µm, f/2.0 

When it comes to the camera, both these phones are pretty strong, but there is an advantage coming from Xiaomi, in that it offers an optical zoom lens on the second camera. On the OnePlus 6T, that second lens is used for depth data to power the aperture effect, rather than giving you any other feature. 

The Xiaomi Mi 8 Pro has larger pixels so notionally can take in more light in the main camera. Both are good, but Xiaomi perhaps has the edge, with its AI mode also helping to boost things. OnePlus is pushing night shooting better with its Nightscape mode, but we expect both companies to keep updating the software features of its phones.

When it comes to the front camera, both pack in plenty of pixels, offer portrait mode and beauty functions.

Software experience

  • Xiaomi: Android 8 Oreo with MIUI
  • OnePlus: Android 9 Pie with Oxygen OS 

The software approach of these two companies is very different. OnePlus has always been about performance and prolonging that performance, keeping your phone running well through its life. 

It's a light touch that puts the focus on Google services for a lean and unobtrusive result. In many ways, it doesn't look too different to a Pixel phone. If you like Android and Google, then OnePlus will appeal.

Xiaomi's approach puts MIUI first, a complete reworking of Android so it looks and feel distinctly different. It adds a lot of features, but also duplicates a lot of apps and services, in some cases adding in advertising that you might not want, and offering inferior apps in place of the Android staple. 

While MIUI runs fast and smooth, OnePlus feels more like Google's Android and we think it offers a cleaner experience - so we'd lean towards OnePlus on the software side.

Conclusions 

The Xiaomi Mi 8 Pro and the OnePlus 6T go toe-to-toe as flagship alternative phones that won't break the bank. At £499, both offer remarkable value for money. In many places, the spec is the same and the performance will be too, but there are subtle differences that might make you choose one over the other. 

We think the Xiaomi design is more exciting (although that's personal taste) and there are areas where we think the camera is a stronger performer - and the core spec for the money is better than OnePlus.

However, OnePlus offers a cleaner software experience so it's a nicer phone to use on a day-to-day basis and the bigger battery gives it endurance that Xiaomi can't match. These two factors may well tip the scales in the direction of OnePlus.

So which will you choose?