The w140 is one of the most expensive Mercedes to maintain since the 600. I know a few people with these cars and they were glad they paid more for the warranties. It is easy to run up a bill of 4-5 thousand on these car for repairs. Also, a warranty gives you the luxury of having any covered problem major or minor fixed right away. You'll never put it off until you have more cash and you'll never have to decide to do one repair instead of another. I still believe that car companies must make a profit or at least break even with the warranties, so some people will get more than they pay for and others will get less from their warranties. I think a w140 owner would be one of the ones to get more out of it.
1995 E420 - retired
1986 420SEL - retired