We used Fabian!!
He went to all the same places as Cosol and Frank. The differences were that Fabian's price was less($45 each), he personalized the tour and we weren't cramped in a van with others. We had it all to ourselves. We moved when we wanted to and not have to wait on others. It was WONDERFUL!!
http://www.fabiantoursstlucia.com/
Great Rum Punch. Great tour and guide.