I am a member because I have to be for certain clients I represent.
If you have problems in joining, as the requirements are pretty strict in having to do work as a warranty provider for a certain number of manufacturers, and proving it, contact me, email is in the profile.
As for classes, I give a couple per year for them. I give a good class on the equipment I rep. (at least I've been told I do)
One thing I did notice, about the classes, It is like any other, you will have to travel to get to them, and pay for it, so unless you do a lot of work for the manufacturer, in my opinion, the costs involved outweigh the benefits.
One benefit I see is that they give you a service ticket form to use, that every manufacturer I know accepts.