This is THE best casino/hotel pool in Vegas I've been to so far...and it is the reason why I get rooms at Mandalay Bay...just to come to the beach!
Lazy river, wave pool, plenty of other pools to soak, and beach sand! Doesn't get much better than this.
Pool bar food is good, not great, but good. Much better than most other pools I've been to...
I've come during the weekends when it's packed, and on weekdays when it feels quiet. It's pretty hit and miss, and will impact your experience...just hope for the latter!
Will probably be one of the highlights to your Vegas vacation! Just do it :)