You were comparing a pair of entry level B&W’s with Vandersteens upper level model. Although the B&W Nautilus are a more expensive speaker they are a big improvement over the lower (CDM, 600 etc) models. This manifests itself through an noticeable smoothness and refinement with none of the grain of the lesser priced models (when used with better quality components, obviously).
I had a pair of Vandersteen 1B's for 8 years and loved them. Last summer I finally upgraded to the 2CE signatures and enjoyed finally having a pair of full range speakers. Until: I heard my brother's new pair of B&W 602 bookshelf speakers ($600 a pair). He was driving his speakers with my older electronics; Melos SHA-1 preamp and a B&K ST-202 Amp, Kimber PBJ etc) Granted, his sound had a bit more grain (much of this probably from his Pioneer CD/DVD player) but the midrange was just so much more involving. These little B&W's' just ROCKED compared to my $2K Vandersteens! Two weeks later I had sold my Vandersteens and purchased a one-year old pair of B&W Nautilus 803's. The 803’s are about twice the price of a new pair of Vandy 2CE Sigs so Vandys are an excellent audio value. My final synopsis is this: My Vandersteens sounded beautiful with Classical, Chamber music & Jazz combos. But with anything heavier, like Hip Hop, rock etc they were just too damn POLITE. They just seemed unhappy being cranked on the few occasions I pushed them. I even experienced Vandy's protective circuit kicking in during an extended Rocking session at my New Years Eve party. B&W’s just seem like a much more fun speaker, happy with ANY kind of music I pump through them.
Another quick story: I have a friend who works at a sound studio here in Chicago. He’s recorded many different kinds of music including lots of Hip Hop lately. The studio uses B&W’s, Manley speakers and a pair of Vandersteens. He’s told me that bands continue to choose the Manleys & B&W’s when mixing. As accurate as the Vandys are, the same music just doesn’t sound as engaging as on the others. Good luck with your decision but make sure you spend a lot of time playing your kind of music on the Vandersteens before you buy!