The Bostons compare well with the competition but it's ultimately up to your ears and what you like. I have a 6.1 Boston set up and I run them on a Yamaha RX-V1400. I really like the sound I get but I am not sure a Denon, Onkyo, Marantz, H/K, etc. would sound any better or worse. You will be happy with any of the receivers you mentioned. They are all very good. If your looking at the Denon 2805, you might include the Yamaha RX-V1500 as well.
Shinerman