I really liked Corona Del Mar. Staff is ever so friendly and helpful to boot! Although they don't have a pool at their location, they do have an understanding w/ Coconuts,next door that their customers can use their pool (at least that is how it was a year ago) A clean beach and I think there is a swim area (roped off) at the end of their dock. Although I didn't go swimming. Most beaches in SP have sea grass, so don't be surprised if you can't find a swim area right off the beach. Just a small price to pay for being in SP.
Corona's rooms are clean, nice and the one we had, had a fridge in it that they kept full of bottled water. It's also close enough to town that you can walk along the beach and just enjoy at your leisure. I can't say enough good things about Corona Del Mar. I don't think you will be dissapointed at all with them.