The LG G4's screen is much bigger (we'll get to that in a minute), but the phone itself isn't much bigger than the HTC One M9. LG's flagship is 3 percent taller, 9 percent wider and just 2 percent thicker.
Despite being the bigger phone, the G4 is actually 1 percent lighter than the M9.
With the LG G4, you have your choice between (likely more expensive) leather and plastic builds. HTC's aluminum unibody design hasn't evolved much over the last 2+ years, but it's still one of the sharpest-looking mobile devices you can buy.
With the G4, you have two color options to choose from within each build.
The LG G4's display is 21 percent bigger than the One M9's. Considering it's only a little bigger and slightly lighter, the G4 gives you a much better phone size to screen size ratio.
This may have been the One M9's most disappointing spec. In a world of Android phones that are increasingly moving towards Quad HD, HTC stood pat with 1080p.
It's not that the M9's Full HD display looks bad on its own, but when you put it next to a 1440p display like the G4's, it's going to look a bit last-gen.
While companies like Samsung and Motorola lean towards AMOLED screens, LG and HTC are both known for IPS panels in most of their flagships.
Apple led the charge for fingerprint sensors in mobile devices (with Samsung following quickly behind), but neither LG nor HTC put them in their latest flagships.
The One M9's rear camera has the higher resolution – and we were pretty happy with its results – but that doesn't mean the G4 won't take better shots (thanks in no small part to the next three categories).
HTC dropped its UltraPixel camera (fewer, but larger, pixels) from the M9's rear camera, but it lives on as a selfie cam on the front side.
HTC skipped Optical Image Stabilization in the One M9's camera.
The G4's rear camera also has a wider aperture than the M9 does.
One of the LG G3's coolest features returns in the G4. When snapping shots with the rear camera, the phone will fire a laser to (quickly and automatically) measure distance between lens and subject. The result is a quick and in-focus shot, just by tapping the point on the screen where the subject is.
The One M9 doesn't have terrible battery life, but it was also far from the best of the phones we've reviewed. Stay tuned for more on the G4's uptimes.
The M9 does use Qualcomm's Quick Charge 2.0 tech to quickly get an almost-dead M9 battery back up to snuff.
We're just looking at one 32 GB storage tier for each phone.
Both, however, have microSD slots – something that's increasingly rare in Android flagships.
The M9's Snapdragon 810 has had some overheating issues – and the back of the M9 would, at times, get pretty warm when we reviewed it. Perhaps that crossed LG's mind when opting for the hexa core Snapdragon 808 in its place.
Both handsets have a healthy 3 GB of RAM.
Accidental damage warranty
You could argue that the One M9's killer feature is its Uh Oh warranty. Included with every One M9 purchase, HTC will give you a one-time replacement if you break your phone's screen, inflict water damage on it or even if you switch carriers. And if you don't use that one-time swap after a year, you get US$100 off the next One flagship.
Both the G4 and M9 have Android Lollipop cores, with respective manufacturer custom UIs on top.
The One M9 has already been around for a couple months. The G4 is available in Korea, but there isn't any exact US release info yet.
Starting price (full retail)
We're still waiting for carriers to announce pricing for the G4.
Starting price (on-contract)
Same deal here. We'd be surprised, though, if the plastic G4 wasn't a $200 on-contract phone. We'd expect a little more (maybe $50-100 extra) for the leather version.