Own at OKW and have stayed at both resorts. Here's my pros and cons:
OKW
pros-
1- rooms are larger
2- rooms are laid out really well (love the full dining table and chairs and laundry room in 1BR and 2BR villas)
3- very quaint and pretty
4- if you request to be near the HH or Penninsular Rd bus stops you can get on bus at HH and go right out to parks...then when you come home from parks, you can get off at Penninsular Rd (1st stop)...this way you avoid the long internal bus ride (not sure there's a way to do that at SSR)***see map below
5- can boat to Downtown Disney
6- takes less points than SSR
cons-
1- long internal bus rides (if you don't get near HH or Peninsular stops)
2- boat to Downtown takes about 20 minutes and does not run very late
3- fake hard wood flooring throughout villa can make neighbors above noisy
SSR
Pros-
1- good dining venues (we like the CS place here)
2- can request Congress Park section to walk to Downtown Disney very easily
Cons-
1- carpeting in villas has been known to hold moisture (folks complain that SSR rooms are muggy)
2- long internal bus rides
3- small villas
4- bland theme IMO
Both are large resorts and you may be in a section that will be far from the main (HH) building/pool/dining/shop. We, personally, prefer OKW. We go for the villa size over the access to Downtown Disney (we don't spend much time at DD). Happy planning!
