SamR:
The beauty of Jam is that you can (should) be able to go to any class in the world and you know that you will get a certain level/standard of both teaching and workout level, hence why the Les Mills stuff will probably stand the test of time.
I hate to say this because I have already discussed basically the same thing in another thread, but I doubt that we can get a certain level/standard of teaching anywhere in the world.
Here in Japan, as most BJ instructors are employees of KONAMI SPORTS, costs to get/sell new releases are covered by the company and such instructors are not likely to endeavour to reach or go beyond the certain level. On the other hand, Zumba instructors seem to be independent ones here, so they are more likely hard workers.
As the population in Japan is huge, a half of the US pop, if BJ instructors fail to get as much market share as it deserves while Zumba instructors are successful, it may easily become the cause of shifting the balance between BJ and Zumba in the world in a few years time. (If China enters, the situation cannot be the same, though.)
I do not understand why LM (or G even) don't check the performance more strictly where most instructors are employees of the sole EXCLUSIVE licensee in one country, especially in the case of a company having strong economic power such as KONAMI. LM may only know the peformance of really good ones, I doubt.
Sorry to keep on saying such a complaint, but I can see that the time is really a turning point in Japan. As I am just a participant, there is not much that I can do. I just want you to know, at least.