First you need to choose location. As suggested I would probably go for West End in Roatan or Utila. The former caters more to slightly better and more experienced divers, as well as a bit more mature people in general. The latter if you prefer younger, more party-like nightlife, lots and lots of young people coming and going every week. Im more of the serious type, and I still had a good time in Utila. It's just cute. To me, Roatan is a bit more "gringo" and Utila a bit more "trashy euro". Also, if you are looking for lots of class experience (assisting), Utila is probably the place. They ran far more courses than Roatan, as a general note: Utila is about learning to dive, Roatan is more about diving. Again, it's the way I see it.
Second, you need to choose the type of shop where you want to do your DMT. You can go to a big shop that runs lots of courses and has a lot os staff, many people, lots of customers, say Utila Dive Center or Coconut Tree Divers on the Roatan side. Or you can do it at a small shop, let's say Deep Blue in Utila, or Reef Gliders in Roatan. The big shop/volume and the small shop experience are quite different. I wouldn't say one is better or worse than the other. It's just two very different approaches to what you learn.
Again, on the bigger shops like UDC you will get LOTS of experience in courses, you will get lots of experience on a multitude of things since they usually run very tight, complete courses. But you will feel like you are one more little bolt in the system. If you do your DMT with Reef Gliders for example, you will get loads of experience dealing with real diving customers (not backpackers that will probably become Instructors or not dive ever again), with more everyday dive shop mechanics and stuff.
It's hard to go wrong. Both experiences are very cool. But you need to decide what your personality is compatible with. Im a bit of an ADD sufferer, so I need constant stuff happening, and that's why many years ago I chose UDC, because it provided me with that non stop "action". You need to choose what you feel you are compatible with.