It was a $tretch getting into the 2803, so the 3803 was never really a consideration. That said, I don't regret anything about the 2803.
As far as features and connctions, I have more than I can come close to using. But they seem to keep the upgraditis at bay. I like knowing I can use the rear surround channels as a separate zone, for example. And little by little, I'm learning more about it, without ever feeling like it's lacking.
I can't guarantee that the 2803 will sound as good as the 3803, but I think you'll find the Denon's 90wpc will still sound better than the Yamaha's "110." (From what I understand, Yamaha's power ratings are based on one channel driven; Denon's are more understated and "truer" into multiple channels.)
As to the power supply question, I haven't had any problem with it heating. It hardly gets even noticeably warm, nevermind excessively hot.
Happy shopping,
Roger
