I bought an 87 190E with 135k miles and did a further 50k as an everyday driver. This was a euro 2.0. I found it had quite respectable performance and reasonable fuel consumption.
I kept on top of the routine maintenance and it only let me down once on the road when the alternator died (only 800 yards from home!)
You can buy an unreliable MB, just like you can buy an unreliable Honda, Toyota, Ford. But reliable ones are out there, too. I think that they are less forgiving of poor maintenance than your average Japanese car, but much more rewarding to drive. If the previous owner has not kept up with the maintenance, you can end up with a backlog of small jobs that add up to a pile of cash.