The usual advice is "buy where you want to stay." But I prefer the slightly easier-to-satisfy: "don't buy where you wouldn't be happy to stay." If you can see yourself enjoying SSR but would sometimes prefer other places, that's enough to be able to buy there IMO. If you can't imagine enjoying SSR, that's a different story.
This is a critical point. And related to the imbalance we see at 7 months due to popularity. If every DVC was equally popular, then there would be equal availability at 7 months...
But in reality -- Tons of SSR/OKW owners flood the demand at 7 months, looking to book anyplace except SSR and OKW..
While very very few GFV or BCV owners are looking to book at SSR/OKW at 7 months.
If GFV is your preferred resort: If you buy GFV points, then you are virtually guaranteed GFV. If you go cheap with SSR points in order to use them at GFV, you're gambling. You saved money buying the cheaper points, but you're effectively entering a lottery at 7-months as to where to use them.
Beyond not getting what you truly want, there is also another danger of "buying cheap" actually becoming more costly:
Lots of talk on this thread about good availability of 1 bedrooms at 7 months.
Very true. But 1 bedrooms are darn expensive on points.
Do you really want a 1 bedroom at BCV, GFV, RIV.. etc.... or you're booking it because it's the only thing available at 7 months?
For example, if I were to book a standard studio tonight at Riviera -- 17 points. But if the only thing available is a 1 bedroom preferred-- That's 45 points per night!
Buying 17 direct points at Riviera is actually much cheaper than buying 45 resale points at SSR!
So I'd say, "Don't buy where you won't want to stay"... but I'd add: Even if there is 7 month availability in 1 bedrooms, "don't buy sleep-around points unless you want to pay 1 bedroom premiums."
The "cheapest" DVC investment is really buying enough for standard studios in your preferred resort. If you buy outside your preferred resort, you're forced to purchase extra to afford 1 BR preferred views.