OnePlus finally unveiled its latest "flagship killer" at an event in June following months and months of rumours. As expected, the OnePlus 3 follows in the path of its predecessor, offering tremendous value for money but is it the right OnePlus device for you?

We have put the specs and our experience of the OnePlus 3 against the OnePlus 2 and the smaller OnePlus X to see how they compare and what the differences are between the company's devices.

The OnePlus 2 measures 151.8 x 74.9 x 9.85mm and weighs 175g. It comes in Sandstone Black and there are four covers available to offer a slightly different look. There is also a fingerprint sensor on board, along with USB Type-C. It offers a fantastic build quality and while it isn't the slimmest device out there, it certainly doesn't feel budget.

The OnePlus X measures 140 x 69 x 6.9mm and it is available in Onyx, Champagne and Ceramic, with the Oynx model weighing 138g and the Ceramic 160g. It is charged via Micro-USB and there is no fingerprint sensor on board. It's a nice, slim handset that hits all the right points with its glass and metal finish, but we thought it felt a little cheap in comparison to its bigger, more expensive brother. 

The OnePlus 3 features an anodised aluminium body with slightly rounded edges compared to the OnePlus 2 and its build feels every bit the flagship. The rear camera lens is square and much larger than the OnePlus 2. It is also centralised unlike the OnePlus X, which is round and situated to the left. The OnePlus 3 has a fingerprint sensor housed on the front and it measures 152.7 x 74.7 x 7.35mm and weighs 158g.

This means the OnePlus 3 is lighter and slimmer than the OnePlus 2, but ever so slightly taller. It is quite a bit larger and heavier than the OnePlus X however. There are also two colours options for the OnePlus 3 comprising Graphite and Soft Gold.

USB Type-C is on board the OnePlus 3, as you might have expected, and the alert slider from the OnePlus 2 and OnePlus X is also present.

The OnePlus 2 features a 5.5-inch with a pixel resolution of 1920 x 1080 for a pixel density of 401ppi. OnePlus uses an IPS LCD display for its OnePlus 2 and the results were excellent. It offers ample brightness, a colour palette that feels natural and accurate, as well as decent contrast and viewing angles.

The OnePlus X has a slightly smaller 5-inch display, but the resolution remains the same at 1080p, meaning a slightly higher pixel density of 441ppi, offering plenty of crispness. It is protected by Corning Gorilla Glass 3, like the OnePlus 2, but it opts for AMOLED display technology instead of LCD, which results in rich, deep colours and inky blacks.

The OnePlus 3 offers a 5.5-inch display with a Full HD resolution. This puts its pixel density at the same as the OnePlus 2 at 401ppi, meaning the OnePlus X still takes the crown for the sharpest OnePlus display.

The OnePlus 3 is protected by Corning Gorilla Glass 4 and switches to Optic AMOLED for the display technology, which although different to the OnePlus X, it is still OLED instead of LCD. It results in a panel that is full of colour with high contrast levels, along with the crispness of former devices.

The OnePlus 2 offers a 13-megapixel rear camera with a f/2.0 aperture and a 5-megapixel front-facing camera. The rear camera comes with a 0.2-second autofocus, as well as optical image stabilisation and in terms of image quality, the OnePlus 2 does a sterling job.

The OnePlus X also has a 13-megapixel rear camera but with an aperture of f/2.2, while the front snapper has a higher resolution of 8-megapixels. It's pretty average and not as proficient as the OnePlus 2's camera, with results exhibiting a notable amount of image noise.  The OnePlus 2 is capable of 4K video recording at 30fps, while the OnePlus X tops out at 1080p video recording. Both offer slow motion recording at 720p at 120fps though.

The OnePlus 3 features a 16-megapixel rear camera with an f/2.0 aperture, PDAF autofocus and OIS. It is capable of 4K video recording at 30fps and 720p recording at 120fps and it also offers RAW image support.

In terms of the front-facing camera, the OnePlus 3 offers an 8-megapixel sensor with 1.4um pixels and fixed autofocus. There is also auto HDR, manual control, something called Dynamic Denoise and Clear Image features on board. Overall, the OnePlus 3 produces some attractive shots when focus is acquired, and automatic mode does a great job of dealing with varying light levels.

Previous OnePlus flagships have been renowned for offering the same hardware as competitors but for half the price, and the OnePlus 2 is no different. It features the Qualcomm Snapdragon 810 processor and Adreno 430 graphics under the hood with 3GB or 4GB of RAM support.

The OnePlus 2 is available in 32GB and 64GB storage options with no microSD support for storage expansion and it has a battery capacity of 3300mAh. Everything runs smoothly and responsively, without overheating, and although it impacts on battery life it's not enough to see the OnePlus 2 bow out early in the day.

The OnePlus X also offers powerful hardware for less money than its direct competitors, opting for the Qualcomm Snapdragon 801 processor, Adreno 330 graphics and 3GB of RAM. It comes with 16GB of internal memory but there is microSD support on board for storage expansion up to 128GB via the dual nano-SIM slot. Its battery capacity sits at 2525mAh. Unfortunately, we found the OnePlus X's performance a mixed bag. Watching a video or browsing the web isn't a problem and it's a phone that's typically fluid in its operation, but it shows its shortcomings with more graphically intensive tasks.

The OnePlus 3 has the Qualcomm Snapdragon 820 processor with Adreno 530 graphics under its hood, supported by 6GB of RAM and 64GB internal memory. It's delivers a smooth and super sleek experience, without any stuttering. The battery capacity is a little smaller than the OnePlus 2 at 3000mAh but larger than the OnePlus X and it will get you through around a day and a half. The OnePlus 3 also has something called Dash Charge on board, which is an equivalent of Qualcomm's Quick Charge 3.0 so when you run out of juice, you can get a top up pretty quickly.

Like the OnePlus X, the OnePlus 3 also has a dual nano-SIM slot, but microSD isn't supported. NFC is on board the OnePlus 3 though, meaning Android Pay will work, which it won't on the OnePlus 2 or OnePlus X.

The OnePlus 2 and the OnePlus X both feature a modified version of Android called OxygenOS. It's built on Android Lollipop and is primarily Android but with a few extra customisations and features on top.

The OnePlus 3 also runs on OxygenOS, but the latest version which is built on Android 6.1. 

Features of the software include Night Mode display, Dark Theme and System Accent Colours so the software experience will be very similar across the devices.

The OnePlus 2 starts at £239 and creeps up to £289 for the higher storage capacity, while the OnePlus X starts at £189. There was an invite-only system to buy the OnePlus 2 and the OnePlus X when they first launched, but they are now available to buy without one.

The OnePlus 3 won't be using the invite-only system. Instead the device is available to everyone through the OnePlus website for £329. It launched at £309 but saw a price jump due to Brexit.

Most flagship successors improve on the models that have gone before them. That's no secret and that's what the OnePlus 3 has also done.

The OnePlus 3's design is a more premium than the OnePlus 2 and OnePlus X, plus there are advancements in the power and camera departments, as you might expect.

The battery is smaller than the preceding flagship device, and the display resolution remains the same across the OnePlus 3, OnePlus 2 and OnePlus X, but overall there is enough to warrant an upgrade from either of the previous devices. The OnePlus 3 is OnePlus' best device yet and lays down a marker for what you can get for around £300.