Not to be misleading, but I've had one replacement 3G iPhone and one v1 iPhone replacement. And though I've answered (50) other "like" threads, please do not assume that I've had (100) different replacement iPhones...
3g's I am on my 3rd...I have had 1 with many cracks and 1 with a mic that completely went out after a few months. I had one 2g iphone for 12 months from August 07-July 08... Those were the good old days.