If you’re already accustomed to Benz ownership then you won’t experience anything abnormal with these cars. They’re pretty solid and much less complicated and cheaper to maintain than modern S class, SL, CL, and other high end Benz’s. Other than the obvious things to check for (service records, etc.) I’d specifically look to see if and when the window regulators were fixed, as they all go out eventually; low mileage doesn’t matter here, they eventually all need to be replaced, over and over lol. Check all the door locks and handles, these break/malfunction as regularly as the window regulators. Other than than I’d look for water leaks in the interior and make sure that all of the electronics function properly. Little water leaks here and there can cause interior electronics to go crazy. Oh, and check all the seals and make sure they work (sunroof, door seals, etc).