We love the guitar pool at ASmu and they play daily pool games and music. A HSM song came on and the entire pool (even lifeguards and dads) started singing along! They play an evening movie on an inflatable pool side screen and even wii games in the late afternoon/early evening. The kiddie pool is really close by to the main pool which made it easier to watch both pools at once.
The Fantasia pool at ASmo is also nice and we feel has the best "kiddie" area with a more zero-entry type pool and splash fountains. We do find it to be a tad on the "boring" side but the kids really seem to enjoy seeing Mickey while they swim!
ASsp pool is more of a free form pool like you'd find at any I-4 hotel/resort. We like the overall "surf" theme though and its VERY close to the main buidling which is great for grabbing a pool side snack or mug refill. The kiddie pool is your simple, round, dip pool.
I'd say all three other pools are on the same par with each other, but the baseball pool at Sports is a favorite. AMAZING theming in that section and a great treat if you have some baseball fans traveling with you!
Chair wise we do feel that the guitar pool at ASmu is best for this. It has more of a "pool deck" feel to us with chairs and tables lining both sides of the guitar and even on some parts of the end. We were able to find a chair easy in the peak of the afternoon on a sold out day in September. Either way, I think all 3 have plenty of chairs to enjoy the afternoon.