I just bought a G3 this weekend, and it does get quite warm. Right after activating it, my Google account automaticlly installed all the apps I had on my Galaxy S4. In th emiddle of that process I was palying arouind with it and it would not let me increase the screento overheating issues" is what the little balloon said.
I love everything else about this phone but, even though I have not seen that messge again, the heat worries me a little. Just a little bit ago, I was working on the phone and ended up calling my wife. It was quite warm to my ear as well as my hand.