LG announced the LG G4 at the end of April, bringing with it a 5.5-inch QHD display, Qualcomm Snapdragon 808 processor, 16-megapixel rear camera and 8-megapixel front camera. It joins the January-launched LG G Flex 2 in the company's line-up of flagship smartphones, but how do they compare?

The most obvious difference between the LG G4 and the LG G Flex 2 is of course the normal versus the curved format, but how do the other specs tally up against each other? We have crunched the numbers of the two flagship smartphones to see where their differences lie, how their specs match up and whether design is the only factor separating the two.

The LG G4 measures 148.9 x 76.1 x 6.3mm, while the LG G Flex 2 comes in at 149.1 x 75.2 x 9.4mm. This means the LG G4 is slimmer, slightly shorter and a fraction wider than the LG G Flex 2, but it isn't just about the numbers when it comes to these two devices.

The LG G4 was designed to fit the contour of your hand, offering a gentle curve but it's the same approach the company takes with the LG Magna, rather than the LG G Flex 2. The G Flex 2 has a much more substantial curve to it and a more obvious one. In fact, the G Flex 2 has three curves - the display which LG claims is the same as its curved TVs, the back and the centre line detailing. The G Flex 2 is also flexible, hence the name, while the G4 is not.

In terms of weight, the LG G4 weighs 155g compared to the LG G Flex 2 that hits the scales at 152g, so the G4 is slightly heavier, even if you're only talking a couple of grams.

When we reviewed the G Flex 2 we thought it was unique, distinct, and something a little different but the G4 is a good-looking smartphone too, especially in the leather finish. The rest of the spec comparisons below probably don't matter all that much when it comes to these two handsets as you'll either love the curve of the G Flex 2, or you'll prefer the subtlety of the G4, but we will continue nonetheless.

Both the LG G4 and the LG G Flex 2 feature 5.5-inch displays, but that's the only common factor. The LG G4 has a 2560 x 1440 IPS Quantum display that delivers a pixel density of 534ppi, while the LG G Flex 2 has a 1920 x 1080 P-OLED display for a 400ppi. This will mean that the G4 will have a sharper and crisper display than the G Flex 2, but the G Flex 2 has a curved format.

We weren't overly impressed with the display on the G Flex 2 when we reviewed it but it wasn't down to the resolution. We found great contrast and some deep black levels, as you would expect from an OLED display, but things became a little grainy when the brightness was dimmed. At full brightness, there was a lot of vibrancy and good punch to colours, but in auto-brightness, the grain meant the viewing experience wasn't as good as the LG G3, even if the contrast was better.

It's also worth mentioning that we noticed a slight discolouration on the LG G Flex 2 so we have our fingers crossed that isn't the same for the G4 and its new IPS display. LG claims to have delivered a 20 per cent greater colour gamut, 25 per cent more brightness and 50 per cent greater contrast with the G4 however, so we'd expect the G4 display to win the contest against the G Flex 2.

Camera is one of the features LG focused on heavily for the G4, introducing a 16-megapixel rear snapper and an 8-megapixel front-facing snapper on the new flagship. 

The LG G Flex 2 takes the G4 on with a 13-megapixel rear camera and a 2.1-megapixel front-facing camera, so in terms of selfies, the G4 should theoretically be your better companion.

Even though the G4 wins in terms of megapixels on both accounts here, it isn't just about the numbers in this case either. LG introduced a larger aperture for the G4, with a maximum of f/1.8, which is larger than its direct competitors, including the G Flex 2. This should mean that low-light shots will be better on the G4, but that's not to say the G Flex 2 doesn't perform well.

When we reviewed the G Flex 2, we found the rear camera gave excellent results in both good light and low light. Things got a little softer when the light dropped, but the results were still passable so we have high hopes for the G4 when it comes to rear camera. In terms of the front camera, the G Flex 2 didn't perform as well here. In good light, we got some good selfies, but in low light, the detail lacked compared to rivals. With a big bump in resolution on the G4 though, we'd expect to see better things from new flagship's camera.

LG has also introduced a number of software enhancements when it comes to the camera. You'll be able to save in RAW format on the G4, as well as shoot in three modes including Manual that allows you to adjust the shutter speed. These kinds of features may not appeal to everyone, but if you're looking for a smartphone camera that has fancy tricks on board, the G4 has a few extra in comparison to the G Flex 2.

Under the hoods of these two smartphones, things are almost identical, except for when it comes to the processor. Both have 3GB of RAM, 32GB of internal memory with microSD support for storage expansion and they both come with 3000mAh batteries.

While you might expect the LG G4 to have the faster processor given that it is a 5-month newer device, this isn't the case. The LG G4 features the hexa-core Qualcomm Snapdragon 808 processor, while the LG G Flex 2 opted for Qualcomm's latest octa-core Snapdragon 810 processor. 

The G Flex 2 was the first handset to arrive with the 810 processor and in theory, it should offer blistering performance but while we found it swift in operation when we reviewed it, there was the occasional stutter. With a couple more cores, the G Flex 2 should be slightly faster than the G4, but we suspect the G4 will be just as good a performer, even if it doesn't offer the latest chip number.

Both the LG G4 and the LG G Flex 2 offer Android Lollipop, but the G4 will come with LG's latest UX 4.0 user interface. The new interface introduces a number of features including Quick Shot that allows users to take a picture with a double press of the rear volume button, without having to wake the display up first.

Other improvements include the calendar, Smart Notice for more personalised notifications, along with greater customisation in terms of the gallery and of course the camera modes we mentioned earlier.

LG has not yet announced whether the new UI will be coming to the LG G Flex 2.

The LG G4 and the LG G Flex 2 aren't too dissimilar, apart from when it comes to physical design. The actual footprint of both is near enough the same, give or take a couple of millimetres, and while the LG G4 is slimmer, the LG G Flex 2 is lighter.

The displays are the same size and while the G4 has a higher resolution, which should mean a sharper and crisper image, the G Flex 2 offers a curve instead. Both have the same storage, the same battery and they both offer the same RAM support but the LG G Flex 2 has a faster processor.

It's the camera where the G4 takes a few strides ahead of the G Flex 2, delivering more megapixels and a larger aperture on both the rear and front snappers, as well as a few software extras. The G4 also comes with LG's new user interface but this isn't likely to be a deciding factor as both come with the latest version of Android.

The decision between these two smartphones probably won't come down to the specs. It will come down to which design you prefer. Do you want something unique and different, or do you want a smartphone that could offer one of the best cameras out there at the moment?