Last went in 1999 and haven't been back since. My experience is based on a long time ago, but from all reports nothing much has changed.
We were staying on I-Drive that year, so went there because it was closer. It was also our first holiday to Orlando, and wanted to try everything and squeeze in as much as possible. At the time, we thought it would be our only trip there ever (10yrs later we are DVC members!

)
Anyway, we went over Christmas/Millennium, so it was reasonably quiet, but even so, it was still busy. There were always queues for the 3-slide one, where you climb up the staircase. There is concrete everywhere, so the sun is reflected on you from the ground and the water, and there is very little shade anywhere.
Despite being there first thing, the deck chairs were nearly impossible to come by, and I think we ended up having only two between the three of us. Never had trouble with finding one at Disney, even after turning up in the middle of peak time.
There is a good mixture of rides, and the kids section always looked really good. There are a few more exciting rides that they have added since that time, but haven't experienced them.
My mum hates the place because she is always getting injured over there! She fell when getting into the big family raft ride and cut her hand on her locker key. They were very good about getting her treatment for that though. Then, she had trouble with one of the single raft rides that comes out into a deep pool - the one where the waterfall runs along one side - her tube flipped up and she fell out and had to have the lifeguard get her.
She didn't
feel safe there afterwards, so we never went back. We tried out BB in 2001 when we went back, but were very tentative given our previous experience, but the feeling and atmosphere was so different at Disney, that she was up for anything including Slush Gusher (would have been Summit Plummet, but they had closed the queue because it was getting to the end of the day)
We didn't use the changing areas (came and went in swimwear), so can't comment on those, but did use the bathrooms. They were not clean, at least not to WDW standards - just your usual public toilet. Someone also had a gastro-related problem, which had not been reported/cleaned up. It was at that point we left the park, reporting the toilets on the way out, although no one seemed in a hurry to sort it out!
Unfortunately, I think given the choice of a straightforward square swimming pool or a trip to WnW, we would all choose the swimming pool! Sorry I don't have anything more positive to add!