If you are considering a 210, I would suggest you just go for an E320. They are much more plentiful and lower priced. There is no material difference in fuel costs between the two. I've owned both a '98 E300 and '01 E320. The m112 needed spark plugs less frequently than the OM606 needed glow plugs. The E320 (a wagon) delivered about 23 city and 28 highway MPG in my use. The E300 sedan did perhaps 28 and 32 (it once got 33).

An early 211 E320 is a solid car with better build quality and much better rust resistance than the 210. It has the same solid drivetrain as the earlier E320. The SBC brakes on the 211 present the risk of a $1500 repair if/when the SBC unit needs to be replaced. Other than that it's a pretty solid car.