I've had a chance to do some listening and movie-watching now with my Ascend CBM-170SEs in front, with the SVS SBS-01s as surrounds (still using the BIC DV62CLR-S with Ed Frias' xover mods as center, will be for a while), and I thought I'd post a few thoughts on the matter. Hopefully my thoughts won't be so upsetting that they'll get the thread closed.
In a word, they're a great match. As my 170SEs break in, they're just getting sweeter, and they're really excellent in my room for both music and movies. They're only temporary until my Swan 5.2s arrive then they're going back up to my mixing studio, but until then I really don't feel like anything's missing and I still feel strongly that they're superior to my B&W DM602 S2s.
I watched Harry 4, and whatever you may think of the movie (I have mixed feelings), the Ascends performed flawlessly and the SBS-01s sound great in back. I also watched Doom just today (silly movie but entertaining enough I guess) and same thing, the system sounds great. Really nothing earth-shattering to report here, I just wanted to say that if you're considering the SBS-01s as surrounds they match my 170SEs nicely as long as I keep them up a few dB, since they're less sensitive.
I also watched about 1/3 of Diana Krall's Live in Paris DVD in 5.1 DTS, and wow, does that sound sweet!!
Breathtaking experience. The Ascends definitely sound bigger than they look, very natural and smooth, excellent imaging, etc. I enjoyed the especially life-like drums and cymbals while I watched her drummer play... He uses brushes a lot on that concert and the Ascends reproduced the detail and shimmer of the brushes on the ride beautifully. Her voice and piano are stunning, and as I said, the SBS-01s filled in the ambiance very nicely and proved to be a fine timbre match. I first heard a bit of this concert at a hifi dealer I like and had to own it. In there I listened to some of it on a set of $12,000 B&W 802Ds ("holy freakin s**t" was, I believe, my impression at the time) and also checked it out on a pair of $2200 Paradigm Signature S4s (also not at all shabby). While of course it would be silly to suggest that it sounded quite as good on my Ascend CBM-170SEs and SVS PB10-ISD sub as it did on the 802Ds, it still sounded amazing and considering what I paid, I'm thrilled with the performance. As for the Paradigm S4s, they sounded great (and feature quite a bit more low end extension than the much smaller 170s) but I would actually have to listen side-by-side to be sure they sounded as good as or better than my lil 170SEs with SVS sub. Seriously, when you can get this much performance for considerably less than half the price of the S4s (not to mention a great HT sub into the bargain), I would have a REAL hard time justifying their price tag. (The S4s do look great though.