Bookner:
I have a Bryston SP-1 that I use for both audio and HT -- infact, I bought this unit specifically because I use the system about 90% of the time for audio, but wanted a high-quality surround processor as well.
I have not done a direct A-B comparison between the Bryston and the Classe SSP-30 or SSP-75, but I have heard the Sunfire on a number of occasions. Between the Bryston SP-1 (now the 1.7) and the Sunfire, I thought the Bryston offered better sound quality in audio-only use, while the surround function was a toss-up (both are very good here, so this is not a criticism).
The design philosophy behind the Bryston SP-1 (and its newer version, the 1.7) was to offer the highest quality audio capability while minimizing the "bells and whistles". The SP-1's circuits are taken almost directly from Bryston's best preamp, the BP-25, which has gotten many very positive reviews from a variety of audio mags. As a consequence of Bryston's design decisions, the SP-1 (and the 1.7) do NOT have video switching, since Bryston believes that video switching circuits degrade the audio signals. Hence, if you want video switching capability, you should not buy the Bryston.
When considering any unit that offers 6.1 or 7.1 channel processing, you should bear in mind that the 6th and 7th channels are matrix formats, and the movie and recording industries have no intent at this time to provide discrete software for these formats. My personal editorial here is that very few home theater environments need, or can accommodate, 6.1 or 7.1 channel formats, so unless you have a really big viewing/listening area, and have the money for more speakers and more amplification, don't put much emphasis on these expanded formats. (Bryston has had an interesting article on their Web site about this issue. They interviewed one of the best-known recording engineers in Hollywood, who stated that the movie and recording industries have no intent of moving beyond the current 5.1 format for the foreseeable future.)
One other factor which may, or may not, make a difference to you: warranty and service. Bryston has the best warranty in the business (20 years from date-of-manufacture, and this is unconditional and fully transferrable) -- and Bryston has arguably the best service in the high-end and professonal sound industry.
The new Bryston 1.7 has some features that were missing in the SP-1, such as 5.1 analog inputs for SACD and DVD-A, as well as Pro Logic II and 6.1 and 7.1 matrix decoding. For more info about the 1.7, I suggest you look at Bryston's Web site at: www.bryston.ca
I considered a lot of pre/pros about 18 months ago (Bryston, Classe, Sunfire, B&K, Rotel, Parasound, etc.), and I purchased the Bryston SP-1 because it did the best job of meeting my criteria for excellent audio reproduction, very good surround processing, and an outstanding warranty. You may have other criteria that are part of your buying decision, but the Bryston SP1.7 certainly deserves a long look.