As for departing from St. Thomas, I agree that VIP Yachts is the best.Kelly is fantastic and goes out of her way to help. Limited amount of sailboats/cats but they also offer motorboats. Great staff, they couldn't do enough for you! And I don't own a boat with them....
Voyage Yachts in Sopers Hole is a great company as well, but VERY expensive. All the cats are very well kept, staff is nice and some of the Catamarans are equipped with A/C.
I agree with Ken about Sunsail, 6 days with a sleep aboard, but it does take a full day of travel in order to get to the BVI's. You actually pay for 6.5 days not 7. They do have other options too but you do pay for it....boat can be taken at 12N if available.