The engine was dropped this year after just three model years in the US. Merc didn't sell many of them in the US despite them being the cheapest E-class, so there's not a great many parts stocked here - expect to have to wait for anything that's diesel specific. Diesel E-classes will return in 2018 as a MY2019 offering, but it will be a completely different engine so the parts situation isn't going to be changing for the better, either.
If you are expecting the smoothness of the classic Merc I6 diesels they sold here in the US, too bad because the 250's an I4. It's definitely a step down as it moans and groans and strains to do things the 350 BlueTec had no problems with despite the claimed power outputs. I've also heard of issues with the start-stop system in warmer climates, dunno how that would affect you.
I would suggest getting a 2013 E350 Bluetec if you must get a recent Merc diesel in the US.
In my little corner of Europe, the absolute vast majority of E classes are E200 and 220 CDI. Same goes for the C, by the way. They've probably made millions of those engines. The 250 version is AFAIK slightly different with a bi-turbo setup and all that but it's still a 2.1 liter 4-pot.
I've been in many, many taxis powered by this lump and I can't say it's very refined, not considering it's supposed to be a premium car. It's also hilarious how the stop/start system makes the entire car rock left and right. :lol:
I like the column shift. There's no real point in wasting space with a big lever when there isn't a mechanical connection to the transmission. I've heard it's pretty common in the US that customers break the selector stalk. They're simply used to driving column shift automatics that need a proper grab and pull to go down from P to D. :lol:
I have the same engine block in mine, but with a turbo less. It's sensible and works out here economically with the way the taxes are put together, but it's not something I chosse out of passion or preference by any menas. In America land I would not hesitate to get the E 350 instead. Some quick googling seems to suggest they are similar-ish in value used making it a no brainer to me.