I use this forum for my CLK, its not as good as this one, the users seem knowledgeable but there seem to be very few daily updates, nowhere near as many as this one. Its good as a reference site though. I think the problem is the forums are split by problem type and not model so sometimes it takes a few searches to find what you want and doesn't give the same feel of community. Anyway have a look and decide for yourself...
http://forums.mercedesclub.org.uk/index.php