Thanks so much for the replies - it is mainly the Disney outlet store that we would be interested in. I am assuming that they are all the same no matter which mall you go to. Closest would obviously be more economical for us since we would be relying on cabs!
They're not exactly the same.
The Disney outlets at OPO and Pr1me are owned by Disney; the Disney outlet at LBVFS is not. As such, the location at LBVFS generally has a very different selection of merchandise than the other two, while the other two have about an 80% overlap.
If you're relying entirely on cabs, I recommend the OPO location. It's the closest of the Disney-owned outlets, is in a very nice, high-end mall, and has a fairly consistent selection of fair bargains.
If you have some extra time and don't mind a little extra cab fare, the LBVFS location is also very close to WDW. But be warned - the selection at the LBVFS Disney outlet is more hit-and-miss than the Disney-owned outlets; sometimes they have some great stuff, sometimes they have nothing but junk. When they do have good stuff, the markdowns from original on-site prices are generally much better than at the Disney-owned outlets.
If you have a car, and lots of time, the best strategy for the Disney outlets is to visit each one twice during a week-long trip, once at the beginning, and once near the end. Each store receives new merchandise once or twice a week, and sometimes you can find a bargain on Friday that wasn't there on Monday. If you find something you want, though, don't pass it up - it may not be there whan you go back! The better the bargain, the quicker it sells.