Funny you should ask that question. About a month ago I was comparing these same two models and since I have always had somewhat of a soft spot for the Yamaha sound fields, especially for movies along with the ability to incorporate an additional amp(which I already have) to add the presence channels for a 9.2 configuration, even though it was a little more, I chose the Yamaha over the Onkyo and haven't regretted it a bit. The video processor in it got a very high rating in reviews and you can make independent picture adjustments for up to 6 individual A/V inputs.
If price is the main issue, I would check the electronicsforless.ca website, an authorized re-seller in the Toronto area that has the 809 on sale for $999.00 this weekend only, check it out. For me personally, and given Onkyo's sketchy reputation for aftermarket support, I would still choose the Yamaha.
