Another problem with the 360?

A friend of mine bought a 360 Premium the other week and after we started playing a game the pad just suddenly disconnected. He reconnected it but it still kept disconnecting during gameplay. So we swapped the battery pack around and the problem seemed to stop. But then he started having problems with the headset, which wasn't producing any sound or accepting speech. Then he could speak but couldn't hear, so we tried it on my pad and it worked fine.

Another friend recently got his 360 back from the shop and apart from it crashing almost straight away he had a problem with his brand new pad (Which he got as compensation from having to send it off as soon as he got it back last time). That pad would sync but the lights would go off on the pad and stay that way.

I was wondering if anyone else has had any problems with their pads at all? I was worried when a 360 came back and broke straight away but can there really be more problems?