I have been studying Chinese for a while, first at university and then at different schools by myself.
I did the Chengde Full Immersion Program with LTL and have to say it was probably the best Chinese study experience I have had.
For me the problem was always that I spoke too much English even when studying in China and was looking for a full immersion experience.
The program was great for that, I lived with a retired lady who had a lot of time on her hands, so we spent a lot of time making food together and talk. She is a real "Chengdenese" and has lived there her whole life and obviously enjoyed showing the city to a foreigner.
She did not speak any English, which was what I was looking for, but I guess for a complete beginner that would have been difficult.
The classes were good too, but I have had similar experiences at other schools. What really made the program great was my host mother and living in Chengde, which feels much more like a "real" Chinese city than Shanghai or Beijing.
For LTL, the thing that mostly stood out was the organisation, from the course organisation to the airport pick up everything worked perfectly.
Would definitely recommend for someone who wants to see real China and have a full immersion program.