While the selection in the Caribbean islands is incredible, you'll no longer find it to the bargain basement pricing location it used to be.
Personally, I like shopping in St. Maarten better because there is no price. Whatever the price tag may say, if there's a piece you like, offer perhaps 25% of the marked price, and see where they go.
The end deal may be the same as on St. Thomas, but I love the bargaining process. Just be prepared to walk out if the price is above what you were looking to spend.