I owned a Denon 2805, and recently purchased an Onkyo 705. I must say that the Denon sounded much better than the Onkyo. And, that new Denon remote may be kinda strange. But, the Onkyo remote is a huge, horrendous beast. The THX certification is useless. The only real advantages to the 705 are the extra HDMI input, and internal decoding of DTS-HD and Dolby TrueHD.
I've been seriously contemplating returning or selling the Onkyo to buy an 888. For me, overall audio quality is what counts. And, in my experience, Denon can't be beat in that regard. From what I understand, the video upscaling is outstanding as well. And, finally, the 888 is just plain nicer looking. The 705 front panel is kinda hideous. The Denon's is classy and sophisticated.
Anyway, that's my opinion. (It just so happens that I'm always right, though.)