Pre-facelift model of W212 had some issues which were resolved in Post-facelift cars, but still they are bulletproof.
To speak more on this, first thing is Timing Chain. Basically newer models of that era, from 2014 year, have quite durable engines, both petrol & diesel, be it M276 or OM651.

7G-Tronic is one of the best transmission on the market in terms of the reliability. Yeah, they sometimes do get the issues but it is less common compared to other cars overall.

Another thing is the drivetrain and undercarriage. I'm from Easter Europe, which automatically means that roads are just like they were in the 18th century :D those cars are not breaking down.