Been having G3 for about 2 weeks now. It feels like a good solid phone but it will be way better when we get AOSP working.
The brightness is good enough to see in direct sunlight(I live in So. Cali so there's sun everyday), I would wish that the phone could actually get a tiny but dimmer at the lowest setting though, seems like when the brightness is all the way down it's a tiny bit brighter than my old phone.
The battery life seems pretty fair, at first it wouldn't last me a day at all but it was new and I was changing settings or modifying stuff throughout the day while playing games or browsing the web.
Sizewise, I've gotten used to it now. The notification panel button added to the nav bar is great as I have small hands. Knock on works flawless for me.
I only use the rear buttons for the volume control and haven't hit the camera once.
I don't see how people are hitting the camera as it not only has a different but also a different texture than the power button.
Overall, great phone but gaming while display is on full brightness will drain the battery like a goldigger with your credit card.