I have no experience with Paradigm but the brand and their products seem very well regarded. Having heard PSB (another well regarded Canadian brand), I am not sure how much of a "improvement" would be worth the price differential for you.
I feel the B&W 602 S3 is a neutral speaker with very good soundstaging, tonal balance and a sweet overall presentation that is neither too forward nor too laid-back. Kind of just right- like a number of other British loudspeakers. As befits the larger driver and cabinet than most other bookshelves, they have decent bass extension (similar priced NHT SB3 goes notably lower but is not as quick or tight). They are not ruthlessly detailed such that they make you pay sonically for having "lesser" equipment upstream- they are excellent coupled with a decent integrated amp and a quality digital source.
Hope this helps. I have little experience with multi-channel sound/home theater so I cannot comment on how they might work in such a configuration.
If you are going to drop $600 US, perhaps finding a way to listen for yourself might be worthwhile?