When DH & I were buying (at OKW), we asked oursleves "If we could never stay anywhere else, could we always be happy here?" The answer was yes, so we bought at OKW.
Take a look at all the resorts, either online or in person. Where do you feel comfortable?
Think location. Where doi oyu liek to be? Do oyu liek to be in the "thick" of things?? If so, think BCV or BWV. Lovew the MK??? Maybe VWL is the spot for you. Spend lots of time at DTD??? Then SSR is the place to be. Like laid back, relaxed, Jimmy Buffet? Then go with OKW.
Consider the extra 12 years at SSR...would that be important to you & your family??? For DH & I, no kids. By the time our OKW contract expires, we'll be about 80 years old, so if I am still able to go to WDW, I'll worry about it then.
IMHO, every resort has its charms. But I tend to be pretty laid-back about travelling. If you are a person to whom view, location, room size etc really will impact your enjoyment of your vacation, thne choose carefully.