The only issue with my wife and I's 'bought-brand-new' G5's is that for mine, the vibration functionality stopped working at some point. I know its been dropped a few times (though I have a fairly sturdy UAG case), so there's a possibility I'm at fault there. Otherwise, no issue at all with ours.
I did get a manufacturer refurbished one for my wife's daughter's line, and the first one while working flawlessly for a week and a half just suddenly died - no power/responsiveness at all, switched battery made no difference and even plugging it in would not light up in charge mode while off. On the 2nd refurb now, so far so good.