Here’s a shot of the school and the study facilities. I saw many, but just a very small percentage of the dozens of schools that operate in Antigua.
They are all the same in that all the lessons are one-on-one. Students and teachers are situated face-to-face or side-by-side, mostly in outdoor space. They will arrange a homestay and any activity you want but it’s rarely free.
They are different in the physical appeal of the space, location, cost, materials. As to the teachers, I can’t say, but I think they are all independent contractors and go wherever they are called to work.
If you’re looking for a school in Antigua: I chose Acadamia Colonial because a friend recommended it. It was fine. On the downside it was noisy in the study courtyard. On the upside it was a fresh, clean place. It’s a small school meaning intimate but not so sociable as some.
During the course of my stay I stopped by many other schools and they mostly all looked very fine too. I heard from my teacher and others that all the schools draw from the same teacher pool. I recommend you get into an email correspondence with the schools you are interested in and see which place feels the best for you.