I owned a Mercedes Benz E300 Turbodiesel Avantgarde Designo with all options you can imagine, it was a dream to drive.
Running costs maintain low and ASSYST warns you when to go to the nearest Mercedes garage. I drove around 30,000 miles a year as a businessman, the only disadvantage of the E class is that they are losing enourmous value after 3/4 years. That's why I bought a new W220 S400 CDI Long, still.
Still the 300 Turbodiesel engine with 177 hp was tuned to a 217pk with increased Nm. I also loved the 300 TD, in 1995 I owned an S300 Turbodiesel, same performance. only a size bigger. For the executive businessman I recommend the 300 TD or an S300 TD.
Have had 2 e class in the last few years. My current E300td is an absolute dream.
That 1975 300d was the best car you had, should have kept it. The w210 will give you problems, you have been very lucky.
If you want a diesel car, Mercedes is great. For petrol cars, especially new models, this is not the case. This is my experience as a car mechanic and owner of a MB 190E 1.8 manual. Constant problems with the injection. Everything else is fine and bulletproof. My previous car a Hyundai Sonata, high miler, never put me in trouble in electrics and injection.
Be careful with rust and automatic transmission in used vehicles. The automatics are not so common in South Europe. From my experience, today a petrol Mercedes is not better than a much cheaper Japanese or Korean car in reliability. MB is the most safe car in the world!! That's why it deserves the glory!!
By the way, MB looks simple car to fix. It is not!! There are many tricky things during repairs, and needs experience. MB dealers are not always the solution...
I owned a beautiful w210 300TD for three years, and it was absolutely stunning. I had it re-mapped and it produced 220BHP, but with an unbelievable 414 lbs of torque. It was reliable and economical (for the power), ranging at 37-39mpg.
I have owned 7 Mercs over the past 10 years, and the 300TD was the best all round so far, although a bit noisy for a Merc.
One of my favourite things about Mercs, along with their beauty and solid elegance and reliability, is that no matter how cold it is, even at -7'C cold start, the heater was blowing luke warm in less than a minute, and roasting hot in 10. Like no other.
With exception of the typical diesel noise and vibrations, I give this car a perfect 10. I have seen w210 taxi's in Cyprus which have done over 250000 miles and still going strong.
Only negative is that the electrics become a bit quirky if the battery goes flat.