OnePlus launched a new phone at an event in London on 16 May. The OnePlus 6 is the latest of the devices that were originally marketed as a "flagship killer", bringing a glass back and plenty of great specs with it.

It has some serious competition this year though, with the likes of Huawei's P20 series delivering excellent finishes and camera results and the trusty Samsung Galaxy S9 and S9+ offering plenty of great features too.

So does the OnePlus 6 live up to the original flagship killer branding? Here it is against the Samsung S9 and S9+. You can read how it compares to the Huawei P20 and P20 Pro in our separate feature.

OnePlus 6 vs Samsung Galaxy S9: Design 

  • OnePlus 6: 155.7 x 75.4 x 7.75mm, 177g, water resistant, glass back
  • Samsung Galaxy S9: 147.7 x 68.7 x 8.5 mm, 163g, IP68, glass back
  • Samsung Galaxy S9+: 158.1 x 73.8 x 8.5mm, 189g, IP68, glass back
  • Notch display design from OnePlus

The Samsung Galaxy S9 and larger S9+ design is familiar, because it's essentially the same as the Galaxy S8. That sees a glass rear curving to meet the curved edges of the front Infinity Display. The S9 and S9+ are both IP68 water and dust resistant.

OnePlus meanwhile, has traditionally opted for an aluminium build in the past but the OnePlus 6 sees a glass rear this time around, layered for a depth effect. Water resistance has also been added, though no specific IP rating has been detailed. 

On the front, OnePlus has introduced a notch design display, whereas Samsung avoided it. The OnePlus 6 has a small notch at the top its screen, like the Huawei P20, which means you're looking at minimal bezels on this new phone but the display isn't uninterrupted like the Samsung Galaxy S9

Where OnePlus does have the advantage over Samsung is in presenting a new and fresh design, whereas Samsung stuck with tried and tested. In terms of measurements, the OnePlus 6 sits in between the Galaxy S9 and Galaxy S9+ in both footprint and weight. It is slimmer than both Galaxy models, but wider than both too.

Of the three phones, it's the smaller S9 that feels the most comfortable in the hand thanks to its narrow build and curved edges, but all three devices feel well made and solid. It may be cheaper than its big-name rivals, but the OnePlus 6 feels and looks as premium as the other two. 

OnePlus 6 vs Samsung Galaxy S9: Display 

  • Samsung Galaxy S9: 5.8-inch, Quad HD+, AMOLED, 18.5:9 ratio, 568ppi
  • Samsung Galaxy S9+: 6.2-inch, Quad HD+, AMOLED, 18.5:9 ratio, 530ppi
  • OnePlus 6: 6.28in, Full HD+, AMOLED, 19:9 ratio, 401ppi

Samsung's devices come in two sizes with either a 5.8 or 6.2-inch display. Both are the same resolution at 2960 x 1440 pixels, although the default setting is 2220 x 1080, or Full HD+. 

OnePlus offers a 6.28-inch display in the OnePlus 6 but it hasn't made the jump to Quad HD, with its latest device offering a resolution of 2280 x 1080, which is again Full HD+. Technically the Samsung devices can therefore push more pixels for greater detail; the flipside is that that consumes more power and might be unnecessary in daily use. 

As mentioned above, the OnePlus 6 has a notched display that has a 19:9 aspect, slightly taller than the 18.5:9 of the Galaxy S9. This is what the notch brings - a little more display space, a little less forehead bezel. The Samsung devices meanwhile have slim bezels at the top and bottom of their screens, but the display is uninterrupted.

Both Samsung and OnePlus displays are AMOLED - with Samsung's regarded as one of the finest displays around - but we've always been impressed with OnePlus' offering.

This year's OnePlus display is vibrant and attractive, but also more accurate than last year. Whites are no longer overly warm and reds aren't oversaturated. Still, it's hard to argue with the extra sharpness on offer with the Samsung phones, although the curved edges do mean that some content inevitably ends up slightly distorted in those areas. 

OnePlus 6 vs Samsung Galaxy S9: Hardware 

  • Samsung Galaxy S9: Exynos 9810/Snapdragon 845, 4GB RAM, 64GB storage + microSD, 3000mAh
  • Samsung Galaxy S9+: Exynos 9810/Snapdragon 845, 6GB RAM, 64GB storage + microSD, 3500mAh
  • OnePlus 6: Snapdragon 845, 6/8GB RAM, 64/128/256GB storage, 3300mAh

OnePlus has been a dedicated user of Qualcomm's hardware and it is therefore no surprise to find the Snapdragon 845 running the show. This platform is supported by either 6GB or 8GB RAM and 64GB, 128GB or 256GB storage options. The 8GB RAM and 256GB storage model is only available on the Midnight Black colour option. 

There's no microSD on OnePlus phones, an advantage that Samsung holds. Samsung has a version powered by the Snapdragon 845 too, although in the UK its phones run on the powerful Exynos 9810, with 4 or 6GB of RAM (the S9+ getting 6GB). 

OnePlus is known for its Dash Charging which is really fast and present in the OnePlus 6 too. The battery size is 3300mAh, which is in the middle of the two Samsung devices with the S9 offering 3000mAh and the S9+ 3500mAh. Both Samsung devices have fast charging and both support wireless charging, the latter of which OnePlus does not.

We've been really impressed with the OnePlus 6 battery life in everyday use. We comfortably got to the end of a day, even on days with heavy use. The smaller S9 struggled in that regard, but the S9+ is better, offering fairly similar performance to the OnePlus. 

OnePlus 6 vs Samsung Galaxy S9: Camera 

  • Samsung Galaxy S9: 12MP, dual aperture f/1.5 to f/2.4, OIS, 8MP front camera
  • Samsung Galaxy S9+: Dual pixel camera 12MP + 12MP, dual aperture, dual OIS, 2x optical zoom camera, 8MP front camera
  • OnePlus 6: Dual rear camera system, 20MP + 16MP, f/1.7 aperture, OIS, 16MP front camera

The camera is often the area where smartphones are judged. The Samsung Galaxy S9 is a good allrounder with a skill for lower light conditions from its singular 12-megapixel sensor, while the S9+ has an extra 12-megapixel telephoto lens, allowing for the added advantage of 2x optical zoom.

Both the S9 and S9+ have OIS, with the S9+ offering dual OIS and both Galaxy devices have a dual aperture system which is technically innovative, although we're not totally sold on it being essential. The S9 and S9+ also offer super slow motion video from their rear cameras and they both come with an 8-megapixel front camera.

The camera therefore is the area where OnePlus needs to compete a little harder. A dual camera system is on board the OnePlus 6 with a pairing of a 16 and 20-megapixel sensors. Optical image stabilisation is on board, and the main rear sensor is 19 per cent larger than the OnePlus 5T's main sensor. It is also capable of super slow motion 720p video.

On the front, the OnePlus 6 has a 16-megapixel sensor with an f/2.0 aperture. There is no iris scanning on board like the Samsung devices, but the OnePlus 6 does have a Face Unlock feature.

Few cameras offer low light performance as impressive as Samsung's latest phones. They draw in a lot of light thanks to that f/1.5 main camera. OnePlus does well in most conditions, especially with the use of its Advanced HDR. 

OnePlus 6 vs Samsung Galaxy S9: Software

  • Android Oreo with modifications

Both OnePlus and Samsung run Android devices with plenty of modifications over the top. The Samsung Experience UX is probably the most comprehensive mod that you'll find on any phone, changing pretty much everything about Android, as well as adding more out-of-the-box functionality than any other device. 

But some feel it's a little too much - Samsung owns that experience - and OnePlus has a slightly different software approach. OnePlus' Oxygen OS is comparable, but preserves a little more of Android, adding a few useful features without such a heavy treatment.

When it comes to updates, we think that OnePlus has the slight edge - Samsung isn't especially fast to update Android versions, but OnePlus has a better track record, regularly updating software with new fixes, performance enhancements and security updates.  

OnePlus 6 vs Samsung Galaxy S9: Price

Now we get to the crunch. The Samsung Galaxy S9 and S9+ are among the most expensive handsets on the market. You get a lot of phone for your money and it delivers one of the best experiences around, but there's no avoiding that it's expensive - even if there are some great deals to be had.

OnePlus has always been cheaper, significantly so. The OnePlus 6 starts at £469, which is £20 more than the OnePlus 5T started at but it's still great value for money. The 8GM RAM/256GB model of the OnePlus 6 will set you back £569.

OnePlus 6 v Samsung Galaxy S9: Conclusions 

These phones have numerous similarities. They both have large displays with an aspect that fills the front of the phone, they are both AMOLED, although Samsung has the edge with resolution, giving you more detail. 

Both offer a glass design and both have waterproofing, though Samsung is likely to have the edge here too with a higher IP rating. In terms of absolute design, we can't fault OnePlus - the quality of recent devices has been very high, and it's hard to fault Samsung here too, though you do pay more. 

With both offering similar power, Samsung's advantage comes down to offering a microSD card slot - though you can buy a 256GB OnePlus 6 for £300 less than a Samsung Galaxy S9+. 

The real differentiator we feel will be the camera. We can't help feeling that Samsung offers the better experience here when it comes to functions, speed and absolute quality. However, the OnePlus has raised its camera game considerably - and you can't ignore that price - choosing OnePlus will leave you with cash in your pocket compared to the latest Samsung flagship and the daily experience in most ways matches the Samsung. 

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