The display quality on the G3 did not impress me. Don't get me wrong, it's awesome...but not any better than any other high end 1080p display. The Nexus already has 440+ppi.
Yeah, QHD is a bit over the top and kind of a luxury item I guess... but I will say this, the display is still incredible. It's the size and packaging that impresses me as much as the resolution (which is insanely fine). LG got a 5.5" display in the same relative chassis size as the other 5" flagships.... I still have my wife's 5, and back to back, you can tell a difference, mostly with text heavy apps, like Tapatalk, Google+, etc. But the 1080 displays are still quite good, QHD isn't really that necessary, but it's pretty cool to look at still.
I really only had two gripes with my Nexus 5; the camera's focusing issues and the small battery. The G3 completely solved my issues on both counts, and by a wide margin... the camera is incredible, and the battery performance, even with that monster QHD screen, is substantially better than the 5.
I have no doubts that the G3 is a better phone than the Nexus 5, but that hardly means that the 5 is bad.... If someone told me today that I had to trade on my G3 for something, I'd pick the Nexus 5 without the slightest hesitation. I'd be a
perfect phone if the Nexus had a 2800+mah gas tank and didn't focus like it was stoned half the time ("huh? Wha? Oh dude, sh**, you want a picture, OK, hold on.. Ready!. *click*.. she looks all fuzzy, that's awesome dude. Wait, you wanted that pic? Sorry man"),.... but, alas, it does not.