Cosmo-one of my favorite places to stay and I love both pools...I think the boulevard pool is bigger and in the South tower (that was the old name can't remember what they call that tower now).  The boulevard pool has more chairs as there are a few levels. When I have been it was mostly adults.  If you don't want to be around drunk college kids then stay away from the Marquee dayclub pool-that is where all the parting goes on.  The marquee club is in the south tower like the boulevard pool and is near the boulevard pool but I think a floor down.  The Chelsea pool is on the 14th floor in the other tower.  Pretty much the same experience as the boulevard pool, nice atmosphere and not a lot of kids.  Chelsea pool has some nice day beds right next to the pool water.  Both have nice bars at opposite ends of the pools.  I have taken some ladies to both and had a great time at both.  Which ever tower you are staying I would recommend just using that tower's pool.  If you are coming from another hotel then I would probably go for the Boulevard Pool.