I bought my 300D for five reasons.
1) It burns #2 diesel fuel
2) It has a cast-iron cylinder head
3) It does NOT have a timing belt driving the camshaft
4) It gets double the fuel economy that my old 6.9l E-350 van did
5) It was in my price range
I've had people laugh at me trying to tell me that any Benz is a money pit, but so far it's the lowest-cost-to-operate vehicle I've owned, and after all was said and done, I actually got slightly more for my van than I paid for the Benz. And I"ll openly admit that I love this car.
But I'll admit that, if Volkswagen diesels had a cast-iron head and a timing chain (or better yet, direct gearing), I'd be driving that now.