Well alot depends on speakers and room size. I owned the Onkyo TXsr600 and I now own the Pioneer 811. Difference between these 2 is the Onkyo sounded a tad cleaner but I still enjoy the Pioneer very much. Do a comparison on the two and see what you need to get out of the receiver. If you can listen to them on the same set of speakers at a store do it...and listen with a movie/music cd you know very well....that will tell you which one you like. The one thing I like over the onkyo is the remote that comes with the Pioneer.....it works with everything I own.
Go for the Pioneer, if only because it has full channel pre-outs. You can add a two-channel amp later on for your mains and get outstanding performance.