Renting a villa for the day is really more for someone who truly wants a lazy and pampered day! The condition of the water (either location) will be reflective of any recent storms (or lack of them). Ideally, it would have rained plenty the previous evening and then calmed overnight! Floating on a mat was good the day we were there.
If we are wanting to be more active while at GSC, we skip renting any villa or cabana, and hang-out at the area near the cabanas (wood structures), or even the main beach (nearer the Snorkel Park), bringing our own gear with us. There, you can mix things up where the volleyball court is being used, music is blaring, food and drinks are available nearby, or wander off a little for a quieter spot.