we own at both but prefer the BWVs.
we find the BC lobby and common areas much more busy and noisy (we also found it harder to sleep because of the all-hours-of-the-night talking/yelling in the BCV hallways). SAB can get very crowded, and it can be difficult to keep track of multiple children (the slide entrance is outside the pool area). our favorite resort in that complex is the YC, which we feel actually loses some of its appeal b/c of SAB.
BWVs has a community hall with video and board games, DVD rentals (free for
DVC members), ping-pong, bike rentals, etc.
views are definately better at the BWVs. with a BW view, you can wake up to the sun glistening on the lake with Spacehip Earth in the background

, and watch illumination fireworks bursting over the "eiffel tower" each night.
some ppl prefer the close parking at the BCVs, we prefer not to see (or smell

)cars while at our resort. they have improved the security at BWV resort guest lot, so non-resort guests can no longer park there as easily (thank goodness!

). we timed it to an under five minute walk from the lobby to whereever our car is in the guest lot.
we really enjoy having so many options at our fingertips at the BWVs (jellyrolls, surry bikes, carny games, belle vue lounge, big river grill (yum!), street performers, ATL, bakery, etc) , along with a quiet resort interior and lots of nooks and crannies to read, rest, people watch, etc.
both have easy walks (or ferry) to DHS and EPCOT - the difference in walking distances to these parks is minor.
hth