I have one question.....how old are you?
If you are young enough to reap the benefits from the longer contract, this IMO is a BIG consideration.
Without a doubt, I am a HUGE BWV fan/Epcot resort fan. I am also one that location, amenities and the ease and luxury these things provide for the guest are very, very, very important factors to me in regards to a resort. However, with things they way they presently are, with the exception of certain times of the yr and certain villas (GV & boardwalk view) you can usually book to stay at any of the DVC resorts at the 7 mo window. Just because your home resort is SSR does not mean you have to stay there all the time. Of course no one knows what will happen as more and more SSR contracts are sold and how this will effect the booking availablity of rooms at the other DVC resorts. There is a possiblity that some of the other DVC resorts might one day become almost impossible to book w/o owning there, or DVC could change the rules that you can only book at your home resort-- both most likely will never happen. But these are things that are also a big consideration. If you had to always stay at SSR would you be happy, if not then the extra years are a moot point.
I am glad I am not a first time buyer and young enough to be able to enjoy the extra years (well the young enough part I am not glad about, LOL), because the extra years would be a BIG temptation due to the fact you are getting more time/vacations for your money. However it would have been a dilemma for me because I know I would not want to stay at SSR the majority of the time and taking the chance of booking BWV, BCV or WLV all the time could be like playing Russian Roulette.