We own both OKW and SSR. We have never stayed in the SSR. They are newer and probably more what most people are used to in a condo timeshare layout.
We love OKW because the decor and the layout feels more like a home than just co-joined rooms. I love the ambiance, decor/color scheme and especially love the giant tubs with the shuttered window that looks out to the BR. It doesn't have any purpose, I just like it.
Also love the kitchen layouts in the 1BR and up. The studios are just plain and more like a hotel room, but the other room types have a homey feeling that I haven't found in any other location,
DVC or otherwise. This extends to the grounds, the plantings and the layouts. The rooms just have a nicer feeling.
The villas are fabulous. We had a family reunion there with 9 and had the best time. I saw a post before that said things at OKW were getting a little worn, but am sure that with the maintenance things are pretty well kept up.
The highlight for us when we stay at OKW is the ferry that takes us to Downtown Disney. We love to go over for dinner or just to pop in to Disney Quest. Sometimes the boys go over on the ferry and I will drive out late to go pick them up. A little quiet reading time for me and fun for them.
Either option OKW or SSR is sure to be good. SSR was beautiful when we toured it. We try to go to a different resort/hotel or room type every stay even if it is just for a few nights and then go to our favorite resorts for the remainder.