My first visit was late in the evening on my first trip to Vegas. It was a Monday night and the place was absolutely dead. We were so bored that we barely made it through one drink.
My second visit was much better. We went there for lunch and sat on the rooftop area. The view was excellent, the Margaritas were fantastic and the atmosphere in general screamed Carribean vacation. It was what I was looking for the first visit. I think the key is to go when you can sit out on the rooftop and soak in the rays. It likely helps them sell more Margaritas that way too!