When buying a mercedes benz remember one thing please.
THERE IS NO CAR MORE EXPENSIVE THAN A CHEAP MERCEDES BENZ.
WHY?
lets take a classic example of all Pakistani ads for cars.
car is zabardast, shiny, multinational charya dimaagh CEO driven (CEO has no idea) no maintenance required (warning - this means all pending maintenance has to be done by you now), etc etc etc.
MB takes a special kind of owner, if you dont like to inspect the car before driving off and dont have knowledge or access to proper MB repair shops and parts sources, dont buy it, buy any toyota/nissan/honda and you will be content. I have owned a few, repaired a lot of em and the usual problem is wrong items used to service it, using cheap unbranded parts without update, unknown diagnosis tools, hacked key clones (this is a major problem if one wants to delete a previous key, MB keys are individually coded to the car, cloned keys are imitations of each other - this is a major security risk and it can cause the EIK and DAS to go crazy and lock up, new EIK and DAS are very expensive)
anyway
In my experience, there is no other car built like a mercedes benz, their C and E class drive is what I like - taut yet supple - not smooth - they are sport sedans after all. In all buying experiences and repairs experiences I have found that you cannot cheap out on maintenance as it just costs double as you have to do it in the next few days again (use proper greases/sealants/oils etc) Always make sure your mechanic uses torque limiting ratchets to tighten items and make sure you dont provide made in china parts for repairs.
They are built for incredibly long service life, you can find them in very good order reaching 800,000 kms. I have driven japanese cars for 400,000 kms and others to about 300,000 kms - they were mechanically good but their bodies were gone, stress fractures, bowing, floppy, etc. MB of similar age maintained properly would still be solid.