I've viewed or participated in just about every MB yack site their is.
Some have a single tech who answers when he can - obviously no one can devote themselves to this full-time. Then you put up with alot of yack about childrens graduations, etc. - that's wonderful, but has no place on an automotive yack site. Then you have some sites that are pretty much void of any legitimate tech talent.
Here you have Steve B., Doc, Arthur and others + some knowledgable diyers.
This site is in my opinion the best MB yack site there is. If someone knows of a better one, let us know.