If by JTL you mean "Jamaica Tours LTD.", then I have some experience with them. You can read about it in the following thread:
http://negril.com/forum/showthread.p...?highlight=JTL

In the end, it was cheap, the bus was clean and the staff was professional. That's where the positives end. Others have had different experiences, but our bus did not have any drinks and we did not stop for jerk chicken. Combine than with sitting in rush hour traffic in Mo Bay and a 2+ hour trip to Negril and you have some cranky passengers. I think that a certain segment of the passengers on our bus were getting a little ornery so the driver thought it best to take them directly to their AI resort, without making any stops.

The return trip back to the airport wasn't bad.