Rotax Owners
I am a member of the group and think they are worth the money for the videos, especially for those who are inexperienced or don't do a procedure often.
Having said that, I find it is hard to tell much about who they are. What are the credentials of the posters? A couple of years ago, I was curious about the experience, ratings, credentials and so forth of the group so I searched around the net and found out very little about them - they are some outfit out of Vancouver, if I remember right, but I didn't end up with a list of John Doe, Jack Smith, etc who were A&P, LSMR-A, or whatever, so it's hard to tell their background. One can track some names on the forum and eventually get a sense of the experience level of some individuals, but you still don't have what I would call openness. It's not like John Frank in the Cessna Pilots Association or Mike Busch with Savvy, where you can draw conclusions about the credibility of the author.
From what I can tell, they have no direct ties to Rotax.
I was told that the blog on their site is visible to the public. Check out the top discussion - "Maintenance And Aftermarket Parts" for an impression of how some persons feel about some of the postings. I'm one of the posters in that blog (I am a very rare poster on that site). Roger Lee, who posts here, is one who takes an opposing view.
http://www.rotax-owner.com/rotax-blog
Here is my bias - Rotax is the Apple of aviation engines. It has developed and maintains a cult or mystic about what maintenance can be done by what individuals that is far out of proportion to reality. If you google Rotax Big Bore you will find in the Kitfox site and some German language sites evidence that some people are developing mods to the Rotax 912 and it's accessories.
I operate a Rotax 912ULS in my FD CTSW and two friends have 912's so we frequently have discussions about 912 topics. The attempt of Rotax to control the training of mechanics seems monopolistic, to me. The FAA blocked them from mandating training, so Rotax now tries to keep control through warranty.
No doubt, Roger Lee will post soon and disagree with my observations. Roger is a prime example of a member of the Rotax priesthood. He appears to be extremely experienced and knowledgeable about Rotax engines but is the first to tell you that you can't get all the information you need from Rotax manuals - you need to go to the Rotax schools and hear it from the lips of the anointed.
I went to two Rotax schools and disagree with Roger's conclusions, but we're drifting far afield here.
I think Rotax owners group is worth the money. Caveat emptor.