Can't get enough Benz action...
I think it's worth it because I like the magazine, the Star. Photos and featured cars are often excellent. Not every issue is what interests me but I love it all the same. I don't participate in the events but intend to do so in the future.
The value is highly subjective. This tech forum is light years ahead of the MBCA one so if it's for technical advice, you are better off right here. They do have archives of the magazine and technical articles and reprints that are good. The value depends on what you want to get out of it.
If you want a social outlet and go to rallies, autocross, drag race and show your car, it would be super because these events exist. There are local tune up clinics and meetings. If you want to get involved there is a place to do it.
My late father had over 20 years in a private motorcycle club and they traveled the world by motorcycle. These people became some of his best friends. You may find a benefit there as well. Again, it depends on you and your goals of joining.
'85 SL500 Euro