BCV:
1) Stormalong Bay, This is really quite an exclusive perk.
2) Closest vicinity to walk to an onsite
DVC store/groceries,casual foods to go at the Marketplace. Beach Club is very central to everything around your resort, not a lot of excessive walking.
3) If you buy a Refillable Mug, easiest place to get it refilled several times a day including the Marketplace, Beaches N Cream, and I think the other place by Stormalong Bay that sells food.
4) Walking back from Illuminations is minutes faster, you will be falling on your BCV bed way before you fall into your BWV bed.
5) Same as number one above, this is really quite the Disney Pool.
Buy yourself a pool "noodle" there, and go down the Deep Sand Bottomed Lazy River. Get out of the water and grab ice cream at Beaches N Cream.
Don't go back into Stormalong Bay for at least 30 minutes after eating.
BWV:
1) Nice to be next to all the bakery cafe, candy store, ESPN, and all the other stores and restaurants. Still not as close as the BCV Marketplace.
You will find yourself walking more around this resort, it is quite big.
2) Nice Evening Atmosphere with Jugglers, etc on the Boardwalk.
3) Clown Pool (but truthfully Clowns kinda freak me out).
4) Closer walking distance to Hollywood Studios.
5) Nicer room views if you are lucky enough to get them.