Is the Mercedes Blutec system really that problematic?

[Big Rig]

I posted a few weeks asking on buying advice regarding a 2011 and a 2015 E class.

I also asked on a UK Mercedes forum and pretty much every reply they were warning me off buying anything Blutec from Mercedes, told me to stick with the earlier BlueEfficiency stuff.
Main problems they quoted were NOX sensors failing, around £300 each but that's normally followed by the Blutec pump failing which can be up to £2,000 to replace etc etc.

Surely, that many taxi drivers can't be wrong. There are thousands of them using the E220's of the vintage I'm looking at. Appreciate that I've asked on an owner specific forum so I probably will get more negative responses, so I'm asking for people’s experiences of the system on here.

Is it really that bad?

Car in question is a 2014 E220cdi sport with 40k miles and full MB service history.

[Scrump]

My 2014 E350 bluetec had the NOx sensors fail a few years ago. Not cheap to replace but not too bad in the context of 7years ownership and that is the only big bill it has thrown up.

[Chamon_Lee]

doesn't matter what newish diesel you buy this will be an issue so might as well buy what you feel like.
I had this on a family car we use, on a citreon, 2k for a new tank/pump and around 200-300 for the sensor/injector that was leaking.

problem is this crap crystalizes and causes problems. I am not sure if there is now an additive that prevents this from happened.

[TarquinMX5]

There is a view that UV light can cause the Adblue to crystalize, which messes up the system, including the level-sensor, so the use of fresh Adblue from containers kept in tne dark might help. The problem is that many sellers stock it in clear containers, often left outside, but whether using new, good quality, Adblue would solve all problems, no idea.