I returned mine today (well ordered my replacement anyways). My phone was having issues connecting to the edge or 3g networks. I would have to make 10 "failed" calls before I would receive signal. It was stuck in "no signal" even when it was obviously in signal range. They didn't have any problems ordering me a replacement, should be here over the weekend or on Monday.
Note: they did not see the symptoms at all, or course it doesn't do it when I need it to. Just took my word for it.