The only problem I've had with mine is the controller having to re-sync every so often. This results in a few seconds of lost control in your game. It's fairly infrequent, so it's not a huge deal, but it can be annoying depending on what is going on in your game when it does happen. I also don't really see any excuse for it since the 360 doesn't do that and the Wii, which also uses BT, doesn't do it either. I hope it's something they can eventually address via a firmware update and not an issue that can't be resolved due to hardware.
Other than that it seems rock solid. I'd say my initial impression of the durability of the hardware is that it seems like it will be more reliable than the PSX and PS2, both of which had notable hardware issues at launch. So far I've heard of no mass failures or firmware bricks... and given how popular it is to hate on the Sony right now on the internet, if there were any major issues I'm sure they would have been blown up 100x by now and we would all know about them.