When I first was buying gear, I started out with a Sony STR-DE975 receiver from Circuit City. I quickly discovered it wasn't sufficient for my setup (number of inputs, etc). Thankfully I was within their return policy and I discovered the smaller audio shops. I bought a pioneer elite receiver (their lowest model at the time, this was a few years ago). It sounded muddy. I messed with it forever, but none of my music sounded right and I couldn't ever fix it, so I returned it. I ended up with a Sony ES receiver, which I still love to this day. The sound wasn't different (to my ears without doing an A/B comparison) between the "low end" and "high end" Sonys. I don't know if something was wrong with the Pioneer or if something is wrong with my ears (since lots of people hate Sony amps), but my impression is that there are differences in amp design and some amps do sound different. Next year, I'm upgrading my receiver so I can get the newer bells and whistles and an HDTV, so I'll have to deal with all this again. I'm considering Denon or Onkyo, but I'm hoping the overall "sound" won't change much since I'm happy with my system as it is.