Still using G2 more than 2 years after I first got it. Battery life seems to be a bit less now than when I first got it but the phone still does what it's supposed to do without any issues. Only had to do a Factory Reset when it upgraded to Lollipop. I see me upgrading to the G5 since its closer to the G2 in terms of size. I found the 5.5 inch screen of G4 too big for my liking.
Agreed -- the G3 is the best Android phone I've owned in my 6 years of owning Android devices, and will be the first one I use until it doesn't work anymore, as opposed to upgrading on the 2 year cycle.
Exactly my same mentality for now, although I do want to get into Google Fi which only allows specific phones (due to how their network works) so I may have to try a phone that might have faults.
I have an LG Nexus 5 : common fault is that microphone stops working and power/volume buttons gets stuck (in my case due to case breaking near buttons from being in pocket). I have given Moto G phones to parents and friends - they seem more reliable.