I currently have the 861, I find it to be good. I kind of miss the marantz sound from my old 4002, it seems like it had more punch to it too, which does not lend credence to the Yamaha power ratings. I only got the Yamaha because it was a good deal and it had lip sync (for my new television).
I saw that the Yamaha with 7 channels driven only does 53 watts/channel, whereas the Marantz is actually 90 watts at 0.1 distortion with all 7 channels driven (hometheatermag.com). Isn't that a very big difference considering the Yamaha is rated higher?
Anyways, the Marantz would have lip sync but would end up costing me about 500 dollars more.
Also, I have a vintage marantz 2245 coming for stereo, do you think I should just use that with pre-outs for stereo music with the yamaha? Or should I flip it along with some old textbooks to fund the 5003?