I can only speak from own experience regarding my 1992 300E with 112,000 miles when I bought it in August 2005. The car appeared to be Cherry. The old guy selling it swore it was a "reliable and an excellent car". I failed to take it to an MB mechanic to go over it with a fine toothed comb. My bad.
Since then I have spent over $7000 on the car doing the following repairs over the last year and a half....it's starting to hurt:
New rebuilt Transmission, torque converter, flex disk replacement
New radiator
New coil
Complete Valve job
Complete fuel injector replacement job
Replaced driver's side power window motor
Replaced Becker 1432 Tuner...Twice (DIY)
Replaced Power antenna (DIY)
Replaced Overload Relay (DIY)
Replaced battery and battery tray (DIY)
Complete front and rear brake job
Replaced Oil Pressure Sending Unit
There's more but I can't think of it right now.
Why have I done all of this work? Because I love the car and my wife loves the car. And despite the expense I have incurred, I am still into the car for only about $12,000.

Now the "Pros"

It's a Mercedes Benz and it drives and handles like a dream
This 300E was $52,000 when it was new...that's a lot of car buddy
It's a beautiful automobile to look at because...well, it's a Mercedes Benz.
There is not a spot of rust on this car, anywhere. German Steel baby.

I have thought about trading it in and I actually made it the dealer who would only give me $2200 on the trade. At least you know what you're dealing with, right? But even trying to sell it on the street myself, I would only get about $5000 MAX for it. I'm upside down now.

Be prepared to spend about $10,000 on the car in repairs. If you aren't prepared for that kind of downside, buy a Camry or Accord.
To be honest with you...in hindsight, I wish that I had for one reason....
I DO NOT KNOW WHAT PROBLEMS ARE LURKING BENEATH THE HOOD JUST WAITING TO SUCK UP MORE OF MY HARD EARNED MONEY.

If I could do all of the work myself in my own garage...I would, but I can't.
Good luck. Caveat emptor.