Honestly there is just never a definite answer for every given situation. If you can't book earlier than 7 months due to lifestyle or jobs, then other than purchase price or dues it really does not matter where you own.
I have stayed at all the
DVC resorts and they all have positives and negatives about every single one. You simply have to decide what your wants are, which will be personal only to you.
Fact is that even though some would have you think SSR is in outer Mongolia, it actually is "closer" to all parks than VWL, BLT, BCV, BWV, and AKV. Those resorts are close to one park or in the case of BCV and BWV, two parks but SSR and OKW are close to everything and all the parks. That is not opinion, that is fact based on actual mileage. Now certainly if you have a huge aversion to buses, you have to consider that. But if you wish to visit all parks at some point you will either have to drive yourself or take a bus irregardless of where you stay.
As you age dues will definitely be something you think more about than purchase price. 50 years is a long time to be paying something.
As to Vero being wiped out by hurricane, sure it could happen, but BCV could burn down due to all those crock pots, Forman grills, etc.
So unless you are wanting to book Beach Cottages at Vero, I would say SSR is the best value for the long term use.
Personally I would never buy at a joint DVC-nonDVC resort, as I do not think management takes as much care in them as the stand alone DVC resorts. For example look at SSR, new fire pit, new pool and counter service, new complete rehab of rooms. The rooms at BCV and VWL are older than SSR but they did not get the complete new rehab.