doesn't matter about mileage. you can get 1'000'000 km out of an 80's Mercedes with petrol engine.
- Diesel is more expensive engine.
- Maintenance fees are higher.
- You will have to change your turbos much quicker also. still less reliable than petrol.
- If you make more than 40k km/year it may be worth it otherwise it's just a total waste of money, plus you pay for an engine that sounds like a dog has diahrea.
- All of that not counting the fact that the pollution and toxicity for humans is much worse than petrol.
I have a 2.0 TDI on my VW T6 van and I was "forced" to take it because the shit weighs like 2.3 tons and the only alternative was a 2.0 TSI which doesn't have enough torque. It sounds absolutely awefull.
AAAAAND the worst with modern diesel engine is this bullshit Ad-Blue you will have to tank up every 5k km or so, it's so fucking annoying and expensive.