I would have to check a schedule but I think it probably starts 3/18 through roughly 4/5.

I also vote for Green Valley Ranch. Definitely best for cabanas -- keep in mind that at all strip hotels, cabanas are reserved for "high rollers," you typically CANNOT reserve a cabana in advance. You get on a waiting list, you have to get to the pool early to check the list (this means 8am or earlier), and you still may not get a cabana.

GVR does allow you to reserve cabanas, which is a huge plus. Also, the cabanas have their own dunking pools. Last time I was at GVR, a woman at the cabana closest to ours went topless in the dunking pool, and the staff did not say anything.

Mandalay Bay pool gets LOTS of kids, because of that damn wave pool.

If you are over 30 and have any body issues, you mind find the Hard Rock pool depressing. It is packed with gorgeous men and women, lots of breast implants, very much the L.A. scene. It's great for people-watching, but only if you are very comfortable with yourself and want to laugh at the sheer "over the top-ness" of it all. You might see people having sex in that pool. What disturbs me is that you see people sitting at the swim-up blackjack bar for a LONG time, drinking beer and playing blackjack . . . and drinking beer . . . and never getting up to go to the bathroom. So guess what you're swimming in?

I agree that Flamingo has c-o-l-d water.

Others make a good point about weather, check first to see average temps for your travel dates. "Spring" is a bit vague and you might not want to sit at the pool all day if the weather is so-so.