We're more a north-side bunch...
Francis Bay has a huge mooring field that I've never see full, but I've only been there in the off season.
Trunk Bay is a nice fun day-anchorage.
We usually take a ball in Cinnamon Bay on the first night, after sailing from St. Thomas. Lots of turtles. There are only maybe 8-10 balls there.
We have stayed in Leinster, but not in a number of years. It's very nice and it's fun to snorkel Waterlemon Cay.