We booked our trip through Jamaica Tours - and I am so happy we went with this package rather than the Mystic Mountain zip lining. We did this and the Dunn River Falls tour in the same outing. H'evan Sent is a littler farther away from where we stayed in Ocho Rios, but it really allowed for us to see REAL Jamaica - rather than just the Jamaica you see at a resort or a touristy area. You have to ride through the hills and thin roads where the locals live, which was half the fun of the excursion.
It will definitely push your comfort limits - but it is worth it. The big swing is AMAZING, and the views are even better.
We REALLY enjoyed the staff. The owner, Derrick Evans, greeted us and explained some of the history of the place while we were waiting for the rest of the group. Everything there, the tables, buildings, etc - are made from the trees that fall naturally from storms. They don't destroy the ecosystem there for the sake of tourism, which I really appreciated. The staff members have worked there for years together, and they are very fun and friendly.