MD
I have done courses at the RHC and Bell Academy. Together they both convinced me that this sort of course from the people who know the aircraft best is a really valuable way of learning about the type. Without such courses, I feel that I am likely to be missing something important.
Both these courses had a major element and investment in the presentation of the aircraft technical aspects, so that really high quality training was given about the technical side of the aircraft without too much effort from the lecturer. Pilots fall into (at least) 2 categories: those who want to know as much as the guys who fix them, and those who don't. As a non-aviation engineer, I want to know how it works, so this appeals to me.
I had 2,000 hrs on the Robbos, when I did their course. Did the B206 course with about 50 hrs on type and then went back a while later for a refresher.(I had to pay for both courses myself - no chance of an employer being prepared to pay in this god awful industry! However, I believe it paid real dividends for me even commercially, because I could do the job better)
I have had some pretty dismal experiences with other type courses, even where they have been done by "distributors". It also depends upon the individual you get to instruct you, even at the factory schools.
In practice, though, it is difficult/impossible to do similar courses for some other types. Sadly, some manufacturers do not seem to take the trouble to provide such quality training for their products.