I went diving recently with Protech in Ambergris Caye and they're excellent. Top-notch instruction (I got my Nitrox certification) and equipment (in fact, just the quality of their equipment sets them apart from other shops). Everyone was professional, accomodating and friendly, and very service-oriented.... Plus, what a fun bunch to dive with! I highly recommend them. Definitely check them out when you're there, or send them an e-mail prior to your vacation; I did and got lots of valuable info. Have fun!