There's catolicos and evangelicos. As far as I know, my Dominican host being an evangelical pastor in Puerto Plata, the evangelicos believe the catolicos are not true Christians, one reason being they "worship Mary" and "everyone gets to go to heaven after purgatory". In fact, he was asked to pray at his cousin's funeral, who was a catolico, and he went so far as to say that his cousin would be going to hell because he hadn't repented and been "born again"--an essential evangelico tenet. It was quite awkward in the funeral parlor at that time.
There are other divisions as well within the evangelico camp. Pentecostals, more of the hardliners, have long hair (women) and wear long skirts.
The Iglesia Biblica Cristiana, which is my host's denomination, was actually started in the DR in the 60's (I need to re-read the history of it to be sure). They are more modern--reminds me of a typical "nondenom" in the States. They have all the typical church programs my Virginia church had--married couples, divorce groups, kid's clubs etc. Modern and traditional hymns, communion. The women can wear pants...much more modern in my view.
I've also been to the International Baptist in Santo Domingo and they were pretty rocking--had a great band, reminded me of modern worship services in the States. The preacher was pretty straight--he said, "Look ladies, you are dressing very provocatively, cover up a bit, would ya?" It was refreshing, real-world.
Anyway. My two cents. Could be way off.