Still on my first one that I powered on for the first time on September 5. But hindsight being 20/20, would have liked to try an exchange.
Got mine on wirefly for $199 with no mail in rebates to mess with. Ported my number from AT&T and because AT&T intentionally drug its feet, even though I ordered my epic 4G on August 31, AT&T did not release my number until midnight on September 4, so I could not even start testing the phone until then.
Slider/Screen is a bit loose but I knew I had 30 days to exchange. I went to a few Spring stores and found they were all loose. Waited another week, my wife went to a Sprint store and came home and reported that their Epics were rock solid and the screen did not jigggle like mine when the keyboard was open.
Decided to return for exchange, still within 30 days, until I noticed a fine print thing with wirefly - you have to request a return authorization number(RAN) within 14 days of purchase date (for me, August 31) or you can't return. So I missed my chance and didn't even realize it until it was too late. Luckily, all functions on my phone run great, but the lack of tightness is super annoying....
I suspect they will all loosen up to the state mine is in, if not worse. I have now seen people in the Sprint stores bring theirs back that received a rock solid one that became loose after about 3-4 weeks.
Still really like the phone. Price through wirefly was great, just need to recognize the limitations of a wifefly type situation. I really only had a week to test my phone had I realized the 14 day limitation to request the RAN.