I don't think you'll be able to buy anywhere else but at SSR at thsi point. There is a waitlist at all of them I believe. (I just went through trying to add on.)
If I were buying for the first time I'd want SSR anyway. Longer contract date, plus good incentives right now.
I think the theme pool looks very promising. Zero depth, slide, play water fountain area for the kids. Plus, I like the idea of the food court. The otehrs don't ahve that.
Good luck!