This could be a "volatile" discussion, but before it starts, clarify what you mean by "best".
Best longevity? Best MPG? Quietest? Most Powerful? Cheapest to operate? Most refined? Most able to withstand abuse and infrequent maintenance?
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".