Best Mercedes... hmmm.....
Choice for "everyday" commuting type driving:
I'd have to vote for the W123 body 240D with manual trans. Slug-slow- yes.. but as rock solid, durable and absolutely most bulletproof a car as was ever- OR will ever be built.
Change the oil religiously every 3,000 miles and it WILL run forever!
Choice for "fun" driving:
The vote goes to the W210 E55 AMG. Porsche 911 "balls-out" performance PLUS carry the whole family and luggage comfortably cross-country on vacation. Doesn't get any better than that.
End of discussion!!!