The previous posts mention the "big boys" who do an efficient job of turning lots and lots of charters over. For consistant high quality with more personalized attention you might try Tortola Marine Management at www.sailtmm.com
. Two otehr suggestions for your trip. Start now looking at airfares. I have paid as little as $250 and over 700 for the same trip. Bargins are available. Secondly there is a Best Western Motel in the airport terminal in San Juan. Breaking up the trip down with an overnight stop in San Juan allows a morning arrival, and things just seem to go better.