Not sure why your Yamaha sounds that much better than the H/K did ... maybe it's just your ears, as we all hear a little differently or maybe you had a faulty H/K ...
I currently own 3 Yamaha receivers and I do love the Yamaha sound, the Enhanced modes, etc... really do bring something to the table ... but when it comes down to clean, unadulterated power ... my H/K AVR7300 kills the Yamahas that I own and others that I've demoed, in all audio levels ...
Don't get me wrong ... again ... my Yammies sound great but not when compared to the older H/K flagship 7300 ...
If anyone wants a clear, extremely powerful receiver that is great in 2 channel duty, 7 channel duty for both music and movies (and you don't need the HDMI switching) ... You cannot go wrong with picking up a used Harman Kardon 7200 or 7300 ... I feel they are simply the beastly bargins of the marketplace ...