I don't see any problem with the pairing. If you like what you hear, then get them. Personally I'd mate a B&W with a Rotel, not entirely because the brand is the official test amplifers for B&W speakers. But I've heard the pairing sound superb. Having said that, I think the B&W 600 series or any of their products aren't that choosy with regards amps, provided the impedances match, and the amp power sufficient to drive them.
With regards subs, I use the ASW600. And if you want an all-B&W set-up, the folks at our B&W outlet are raving at the diminutive ASW675 which they say is a lot better than any sub in the 600 line. Try auditioning them.