I have a Marantz SR-19EX surround receiver. I have used it as the main source of amplification for all five channels and also have used it with an Odyssey Stratos HT-3 running the front three channels in my HT system.
The Marantz is very good IMO. For music and movies, I enjoy it, but I mostly enjoy it by itself for movies. It is very smooth and relaxed sounding but it has some ooooomph when you need it when watching movies.
The Odyssey adds more bass punch and a cleaner more refined treble. The soundstage is wider and imaging on 2 channel music is way better. I recently pulled the HT-3 out and was actually surprised at how much I liked the Marantz all by itself for movies.
2 channel music is another story. Stratos all the way. Now if I could start over, I would have gotten a surround processor, an HT-3 and a Stereo Stratos. As it is, I have the HT-3 for the front three and the Marantz handling processor duties and the rear two. I just need another set of rears and can have a 7.1 system in a heartbeat.
There's always something.