Stayed at OKW last year and really liked it. The room wasn't fancy by any stretch, it was a little worn, but the beds were comfortable, the space was good, the kitchen was functional and the balcony overlooking the river was really nice. The stairs were not a problem at all, honestly I am a bit surprised people complain about them so much. Obviously if you have any sort of disability it would be an issue but any other family should be able to walk up three short flights of stairs without any issue (and yes, we carried a double stroller up and down them). We spent one day at the pool, which my kids loved. When we first arrived at the pool we thought we'd be there a couple of hours, tops, but they started a fun pool party and my kids had a blast all day long. The general atmosphere was really nice, my kids loved seeing the geckos in the gardens. Took the boat to DTD once, it was a really fun ride, otherwise we had a car. I don't think I'd stay there without a car, but I am not a bus kind of person.
I can't comment on SSR as I have never stayed there. However, we were originally booked there but switched to OKW because they had the sleeper chair and SSR does not. I wanted all 3 of my kids in their own bed in the 2nd bedroom and knew I'd be able to move the sleeper chair in there but not a sleeper sofa. So, the availability of the sleeper chair ultimately made our decision for us.