Just thought I'd chime in and say that I own the 602s2 and I'm a Peter Tosh fan, and I think the speakers have exceptional performance for reggae music. The metal dome tweeter isn't the best match for bright or harsh electronics (or poorly recorded material for that matter), but I hear great things about B&W/NAD combos and know for a fact that the bass from these speakers can be quite impressive. Granted, I think just about any monitor could benefit from a good sub, but with an adequate amount of power the B&W's do an admirable job with low frequencies in their own right. Never heard the JM lab.
Definitely worth a listen IMO.
Definitely worth a listen IMO.