I went to Intensa to learn Spanish, and the intensive schooling combined with practice in the real world at home and on the streets definitely did the job. Everyone I interacted with outside of school on a daily basis was blown away with the progress I made in such a short time.
I was already living in Costa Rica when I started this program and chose it based on 2 factors: reputation among the locals as a good school and cost. They gave me a great discount because I had friends that were alumni and I was making a typical Costa Rican salary, which is basically nothing. Plus, I planned to go through the whole course and not just a week or two. I went through a total of 10 levels, taking about 3 months.
The teachers were dedicated and really cared about teaching. We did a lot of repetitive work with grammar structures, but we also had free conversation time everyday. For me, it was the perfect mix of technical and practical.
I didn't have 1st hand experience with living situations, but the other students in class seemed to be satisfied. The class sizes were very small - the most students in a class ever were 5, and that was only for 1 week. I usually had the teacher to myself or just another student and me.
I attended the school in San Jose as well as Alajuela. Both urban locations, but there were trips to other towns and the beach. Plus cultural activities, e.g. I learned how to cook some typical Costa Rican dishes. :)