I am not a seasoned pro, as we just bought in this year at BLT. However, we struggled with the same question and after asking a lot of questions on the boards and to my guide etc., I got the following big advice over and over:
- Buy where you want to stay, as your ownership interest is really only in your home resort and "hopping" from place to place is a perk. You never know if all perks will continue in the future (although it's likely it will).
- We booked at the 7 month window for all our upcoming accomodations for May and had no problem with availability for BLT, BCV, or AKL concierge. The availability thread on the DIS is also a great resource for checking out availability trends. I am told it really depends on when you're trying to book for, though.
- the lower maintenance fees and the extra time (almost 20 yrs versus 2042 expiration) made it worth it for us to buy Bay Lake. It was really the time that tipped the decision for us, as we're in our early thirties and decided resale value would be higher with more years on the contract if we decide to sell when our kids are grown or had to sell for financial reasons.
Best of luck with your decision. It was a hard choice for us, but we're really happy with it now.