I agree with the others - I think you'll enjoy either stay.
I've stayed at SSR and visited OKW. My impression is that SSR has a better main pool, but OKW has a better hospitality house. (More compact, open, airy, closer to pool). That said, I love Artist's Pallette and Turf Club at SSR, it's just further away from the main pool.
If you go for a studio, everyone gets a bed, and the studio is larger at SSR. If you for a 1 BR, child gets the sofa bed - but it's still larger. However, SSR has a high level of elegance - but both are nice. Others can say if the Sofa bed is better at SSR than OKW.
As for transportation - I think SSR is more manageable because it's built as a circuit for the most part. OKW has one road the keep meandering back and back and back. While Disney transportation is good and efficient, based on reports at OKW, it would feel longer to me.
At SSR, it's easy to jsut get off at the main stop, hit Artist's Pallette for a snack or beverage, and walk back to your villa. Depending on location at OKW, that would be harder to do there.
All that said, we have borrowed too many points, so we need to stay at OKW in 2008 to balance things out and are really looking forward to it. Hope this helps.
Dirk