i researched it a while ago, and the reviews were mostly very positive. here are some reviews on allears:
http://allears.net/btp/tour_div.htm
the only dissentions seem to be that it is rather short, and pretty pricey - but most would do it again.
btw, i was advised not to scuba OR skydive (asthma), so i took the dolphins in depth course. that one i would advise against: very little time with dolphins, and info was geared more toward little kids despite it being a group of adults. the CMs were wonderful though, and i'm glad i did it once.
on a side note, we LOVED the EPCOT segway (have done it twice), and keys to the kingdom.
have a great time if you do decide to do it!