We randomly picked a dive shop that was close to our resort. We were staying at Vila del Palmar, and picked Scuba Caribe. Being relatively new divers, we're always worried that we'll look like goons on a boat full of professionals. We were both a bit apprehensive when we got to the boat (at the marina) and it was a panga!
We dove for two days, morning and afternoon. The first morning there were 2 other divers on our boat. The first afternoon, there were 2 different divers on our boat. The second day, we had the boat all to ourselves.
Not only were the divemasters super friendly and top notch, they went out of their way to make sure we had fun. During our first surface interval, the DM thought he saw whales, so we spent the hour following whales; having one breech within 100 feet of the boat.
The boat wasn't fancy, but the diving was great ... well, as good as it's going to get in 66 degree water!
I would not hesitate to use them again.