We are on our last day (cry!) of our split stay at WL and BC (both DVC). As others have said, WL is convenient to MK, BC is (even more) convenient to Epcot and HS (5 minute walk to Epcot, 20 minute walk to HS, with options for boat or skyliner).
I would also take into account the vibe; WL is so much more soothing, and “away from it all”, after the hustle and bustle and heat of the parks; and I would say that the dining options there are just fine, especially with mobile ordering/take-out. And the pools, though not “water park”-like, are beautiful, and usually not very hectic or noisy. Plus, you get the electric water pageant (is that what it’s called?) on the lake every night, something nice during the time that we don’t have fireworks.
Beach Club, on the other hand, has are much more energetic vibe, very much like “a day at the beach”, water slide and lazy river, etc. it just *feels* totally different.
I love them both,and I think that you will have a great time at either!