Hi, Alex: This is going to be a marginally useful response, since I have not auditioned the Denon unit. I do, however, own the Bryston SP-1, and have commented a number of times in this forum that I think it's not only an exceptional performer, but a relative "bargain" among high-end pre/pros. The SP-1 lacks some features you may want, however, such as video switching, and a tuner. The decision by Bryston to delete video switching was made because they determined that the high frequencies generated by the video signal degraded the audio quality. As I wrote recently to another person with a question similar to yours, the real issue revolves around the main way you will use the unit. If you are essentially an audiophile that also wants an unit that does a good job with HT surround, then the Bryston is an excellent choice. It has a discrete analog circuit derived from Bryston's BP-25 preamp, plus an excellent digital surround processor. However, if you are more interested in the video side of things than the "purist" audio side, then the Denon may the better choice, although it has a lot of stiff competition (such as the B&K Reference 30 and the Parasound AV-2500).
I hope another A-gon member can give you first-hand feedback about the Denon. In the meantime, I can recommend the Bryston SP-1 without any reservation. I have found the audio quality from this unit, both analog and surround processing, to be outstanding.
You may find it useful to read more about Bryston's design objectives for the SP-1, which is available at this Web address:
http://www.bryston.ca/sp1memo.html