Its been said before and it will be said again, only you can decide what sounds best to you.
Go out and listen to what Denon and Yamaha have to offer in your price range on the same set of speakers and decide which sounds best to you. Both manufacturers have good reputations and loyal followings.
Personally, I saw very little difference sound wise between the two manufacturers. Some will claim Yamaha is "brighter" or that Denon is more "flat". That's where only you can decide what sounds best to you.
To be honest with you I hated both. Before you decide to buy, take the receiver home.
I read all the great reviews about the Denon 3803-05 and the Yami 1400/2400. I bought the 3803 and for three days I cringed at the awful sound that came from it. The Yamaha 1400 was a tad better but not by much. I tested the NAD 753 which was much better sounding but it crapped out on me twice.
I am currently auditioning an Integra which sounds a lot like the NAD and blows away the Denon and the Yamaha.
I guess what I'm trying to say, in an off hand way is, don't rely on reviews alone for your purchasing decision. Let your ears decide.
I will be using Acoustic Energy Aegis Evo series speakers. I know this isn't the speaker forum, but I have a JBL PB-12 which I bought when I was not as interested or informed about HT, and I was wondering how much difference a newer sub would make for my HT. I have read a lot of good things about SVS and HSU but I have never reall heard anything other than what I have and I am disappointed but it constantly. Maybe I have too high standards for a sub but I dont know. Any input would be much appreciated. Thanks!