DiveTech has lots of very experienced DMs who have lots of technical training/certs as well. Of course, most of their business is recreational, so they do that well too.
The difference they offer is shore diving from Lighthouse point. You can book a boat (short drive in bus to dock) or rent a tank and swim out of the sea pool (if it's calm) or jump off of the dock. The diving of the point has a mini wall and not too far from there, the main wall. It's fantastic diving.
I would also suggest if you are even thinking about doing any training, you do it with them. They have a few guys (Mark and another guy who I forgot his name) who are sidemount gurus. Lots of other personalities for less advanced OW all the way up to CCR/Trimix--more than a few women instructors as well if that would help a new female diver. In Cayman, I've found this to be very unique. Most dive operations have good (some great) DMs, but they give you a very confused look if mention Buhlman or anything beyond the recreational realm. I'm not saying they need to be Dr. Deco, just that they have at least the basic knowledge of diving science.
The only criticism i have of DT is that I prefer their larger boat, Atatude, to the smaller. The smaller boat is worn and slower.
In short, they are a great, full-service, eco-friendly shore and boat diving operation.