I would "buy where you want to stay" provided:
1. That you can book more than 7 months out, and
2. That you REALLY CARE where you stay.
If you can't book more than 7 months out, what's the point?
And if you'd prefer one resort, but would be fine anywhere, what's the point?
I think you also need to realize that no matter where you own, certain types of accommodations may be gone exactly at the 11-month mark for certain periods, and owning at that resort is certainly not a guarantee that you will always be able to get what you want.