overall, I love Mercedes, but I wouldn't buy a C-Class. (well, I love Mercedes street cars... absolutely despise Mercedes/McLaren in Formula1)
not other german automobile has the prestige of Mercedes. it's the pinnacle of German automotive engineering (maybe Porsche comes close, but that's apples to oranges). Audi and BMW will always be fighting for 2nd place... sure, they're good driving cars, with better 'road feel' and a better visceral driving experience than Benz, but they still don't command the attention/respect of a benz. you close the door on a benz and it's a solid "thud", the interior's are solid.. non of the squeaks and rattles you get in a bmw (esp 3series). sure, there were a few bad years with electrical gremlins, but nothing like what Audi's tend to have with your dash lit up like a xmas tree (and I love the Audi 6 and 8's).
give me unlimited funds, and i'll take an S65 over a Bentley Flying Spur, Mulsanne, or Phantom anyday.