The studio room at SSR is bigger than the room at CSR, but not nearly as nice. We spent a week at CSR before our FD upgrade to SSR, and if they offered it this year I wouldn't take it. We VASTLY preferred CSR. The beds at CSR are like heaven...the rooms are beautiful. SSR is HUGE, and it was a PITA to walk from our room to the main area to get soda or food. We had to walk along a few interior roads as well. The balcony was tiny and because it was shaded it never really was dry after the afternoon rain. We liked having a dvd player and free movies, but we were there for 16 days- by the end of our trip we were really bored at night.
However, if they offered us a 1 bedroom I would probably take it, as I would love that jetted tub in the master bath.
Also, I just checked WDW reservation service and CSR is completely available my week.