Interesting this topic gets mentioned. Actually the new 4ETS+ system is the most advanced 4wd system on the planet. Here is a link to a discussion we’re having on its merrits:
"We've compared the M class with the G-Wagen...
Also here is an overview of traction control systems:
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In short, other than the lag for going into 4wd, the early ‘90s 4-matic wasn’t half bad, except for the extreme wear and tear it regularly experiences. The new one is too new to really tell but it shows good results and truly revolutionary capabilities so far!