Depends what you're looking at buying one for, really - if its for general road use, and to possibly supply evidence in the event of a crash, then you'd be better off buying something more expensive as you tend to pay for the quality, so the last thing you want is blurry license plates, etc.
Gopro's are brilliant really. No rattles or shake noises from mine and the quality is what you expect full HD
I know its an amount of money but I just waited for birthday