LG has officially announced the LG G4, introducing the third in the line of big flagship smartphones to launch this year. Both Samsung and HTC used Mobile World Congress in Barcelona back in March to show the world what they had produced, while LG let everything settle for a couple of months to launch almost exactly a year after its previous flagship.

In this feature we are comparing the LG G4 to HTC's One M9 to see how the two devices compete against each other, which comes out on top and whether the LG G4 and its 5.5-inch QHD display, 16-megaixel rear camera and 3000mAh battery have done enough to match the competition.

Read on to see the specs crunched and the numbers analysed between the LG G4 and the HTC One M9.

The LG G4 features a plastic body that measures 148.9 x 76.1 x 9.8mm, while the HTC One M9 goes down the metal path and measures 144.6 x 69.7 x 9.6mm. In terms of thickness, the difference between these two handsets is minuscule, but when it comes to width and height, the LG G4 is noticeably larger.

The metal body of the One M9 has its disadvantages however, with HTC's smartphone hitting the scales at 157g, compared to LG G4's weight of 155g, and although 2g isn't going to be the slightest bit noticeable, crunching the specs is a numbers game after all and every gram counts.

Both the LG G4 and the HTC One M9 have their own distinctive design features. The G4 offers a large display in a relatively compact body, along with rear controls, while the One M9 sports its signature front-facing speakers and sleek design. We may not have loved the M9 as much as the M8 or the M7, but it does offer a fantastic build quality that sets a high standard for the G4 and its leather and plastic finishes to compete with.

The LG G4 comes in six genuine leather options including black, brown and sky blue, as well as three ceramic variations, while the HTC One M9 is available in gold on silver, gold and gun metal.

Justifying its larger footprint, the LG G4 boasts a 5.5-inch IPS display compared to the HTC One M9's 5-inch display. Therefore, you get an extra 0.5-inches worth of display for the extra 4.3mm in height and 6.4mm in width.

The LG G4 also gives you more pixels with a resolution of 2560 x 1440 for a pixel density of 534ppi, compared to the HTC One M9's 1920 x 1080 resolution that offers a pixel density of 440ppi.

The HTC One M9 has a great display, despite the company not following the same QHD path as its competitors. It isn't as rich as its predecessors though and while there is plenty of brightness with good viewing angles, colours were a little less muted than the M8.

The M9 also doesn't tick the QHD box, and whether it makes a difference or not on a screen this size, the G4 does, which could be the decider for some depending how much you care. With more pixels per inch, LG's flagship will be crisper and sharper than HTC's offering.

The LG G4 features a 16-megapixel rear camera with a maximum aperture of f/1.8, while the HTC One M9 features a 20-megapixel rear snapper that has maximum aperture of f/2.2. As we said previously, this is a numbers game when you compare the specs alone, but megapixels aren't everything and they don't always mean better results. 

We didn't think the HTC One M9 camera was the best in its class when we reviewed it and while it did well in bright conditions, there were green tinges and image noise in shots that were taken in less than perfect conditions. In a camera comparison piece we did comparing the LG G3 against the HTC One M9 and Samsung Galaxy Note 4, we found the G3 performed better than the M9 in many cases. With LG claiming to have improved the camera for the G4, the new flagship should theoretically also deliver better results despite having 4-megapixels less.

The LG G4 will have a 40 per cent larger sensor, a colour spectrum sensor that the company claims will deliver more natural photos and users will also be able to adjust the shutter speed and save in RAW.

In terms of the front-facing camera, the LG G4 has an 8-megapixel snapper, while the HTC One M9 takes its UltraPixel technology that was present on its M8 rear camera and moves it to the front for the M9, presenting a 4-megapixel snapper. We found the UltraPixel technology was well suited to its task and we had some fantastic quality selfies in daylight from the M9.

LG has made a big play on the camera for the G4 so it will be interesting to see if the extra megapixels will help its new flagship become the selfie king, or whether the extra pixels will be redundant like they are arguably in the M9's rear camera. 

The LG G4 and the HTC One M9 both opt for Qualcomm chipsets but while HTC goes for the latest octa-core Snapdragon 810, LG interestingly chose the hexa-core Snapdragon 808 chip for the G4. Both handsets are supported by 3GB of RAM, but as the M9 has a couple of extra cores, it is likely to be a little speedier than the G4 in theory.

In use, the M9 has a slick and fast experience and nothing we threw at it fazed it when we reviewed it, and we would expect a similar experience from the G4 given this is flagship territory.

The LG G4 and the HTC One M9 both come with 32GB of internal storage with microSD support for further storage expansion. They also both offer relatively large battery capacities, but the LG G4's is slightly larger at 3000mAh, compared to the M9's 2840mAh. We found the M9's battery outlasted the G3's battery, which is the same capacity as the G4, so it will be interesting to see if the SD808 chip does anything to improve battery life for the new flagship.

Both the LG G4 and the HTC One M9 run on Android 5 Lollipop from the box, but you'll get different user interfaces with both. The LG G4 comes with LG's UX 4.0 interface, while the HTC One M9 has Sense 7 on board.

LG has introduced several improvements and features with its latest overlay, including three camera modes consisting of simple, manual and auto, as well as an improved calendar and improved Smart Notice feature for more customised notifications. The South Korean company has also added Quick Shot that allows users to take a shot by double pressing the rear volume key without waking the display up first, and it is also promising greater gallery customisation.

HTC's Sense 7 on the other hand isn't too different to Sense 6 but it moves closer to the Android Lollipop experience. HTC adopts Android's interruptions system but it introduces its on volume controls to avoid some of the pitfalls of stock Android, among plenty of other features.

There are many advantages of both interfaces and as we said in our comparison between the LG G4 and the Samsung Galaxy S6, it will come down to personal preference here. 

Both the LG G4 and the HTC One M9 have their attributes, as you would expect from two flagship devices. There isn't a clear winner as they both offer advantages in certain areas so it depends on which of those areas matter to you most.

The LG G4 has a larger and sharper display, is lighter in build, has a bigger battery capacity, offers a larger aperture on its rear facing camera for allegedly better low-light shots and it features more megapixels on its front-facing snapper.

The HTC One M9 is smaller in build though and therefore potentially more attractive to some, has more megapixels on its rear-facing sensor and includes a faster processor.

We were a little disappointed by the One M9 when we reviewed it as we felt it had been slightly distracted by refinement but it's still a great phone and the LG G4 is more than likely to be great too. Ultimately, it boils down to what your checklist for a smartphone is and which of these devices delivers the least compromise.