I love Tortola, and would gladly spend a land-based vacation there. But to truly understand why we all keep coming back over and over again (14 times for me), you will want to experience the other islands -- JVD, Norman, Virgin Gorda, Cooper, the Baths, the Caves, the Indians, Marina Cay (read "Two on the Isle" by Robb White if you can before you go). Spend a day with a knowledgeable taxi driver (get a quote first) and see it from a local perspective. Have fun and report back!