I had a 1075 (I think) and a Khatargo. The Rotel has a much more relax character, while Odyssey is much more neutral, in my opinion, even a bit bright depending on how you perceive the extended, airy, highs. They take longer to break in before the top end smooths out. I wouldn't call it a "serious" step up although the sound is a bit more open, but there are a lot of other Odyssey fans that will tell you otherwise.
Odyssey amps are heavy (as marketed on their website), but part of that reason is their ginormous aluminum faceplates.