I swim 4-5 times a week and it's a pretty nice pool. I got spoiled in undergrad because my large state school had 2 separate olympic sized swimming pools on campus, but the one in the rec center is very serviceable. They generally keep it at a good temperature and there's a jacuzzi right next to it that ranges from tepid to pretty hot depending on the day. The whole pool area was re-tiled last december so the bottom of the pool is nice and clean. It's 25 yards long and there are 5 lanes. More often than not you'll be able to show up and get a lane to yourself but it can get busy later at night. The lane lines are set up wide enough that it's easy to share a lane though. There have been rare occasions where every lane had 2 people in it, but I think I maybe saw that once or twice all year. I really liked going during our lecture lunch break because I often had the pool to myself, but most people like to actually eat lunch during the lunch break. As an added bonus, every Wednesday night there is a swim class for beginners if you want to learn a new stroke or just some tips on your technique.
EDIT: I forgot to mention the small downsides -- it's closed on Saturdays/Jewish Holidays and the hours are a little more restricted than the normal rec center. They insist on having a lifeguard there so every now and then somebody misses a shift and they have to keep it closed. Other than that though, swimming at Einstein is a pleasure.
