I have a 2010 E350 with 30,000 miles.
It's in the dealership as I type this having the rear airbags changed (under extended warranty).
The service manager at the dealership tells me that most problems with these cars are now age related.
Plastics get hard and break, interior gets sun damage.
The service guy also mentioned that they have more mechanical problems with garage queens.

Generally very reliable
However that generation has a lot of W204 commonality so you can expect some small niggly things to go wrong.
Electronic steering lock and electronics
Command wheel
Seat leather wears out quickly.

M272 and transmission problems were mostly sorted out by 2010

 

The biggest issues would:

Engine & Trans Mounts worn (at 10 years, 100k its almost guaranteed)
M272 Intake Plenum gummed/intake flap mechanism breaks (likely 150k+ miles)
Airmatic Suspension leaks (at 10 years, 100k it likely)
MB-Tex lower seat cushion tearing at stitching (usually drivers side)

Minor Issues:
Rusted Lug Nuts (replace evey few years if it bothers you)
Command Knob doesn't respond to rotation (aftermarket fix, aluminum shaft replacement)
Engine Oil leaks (oil separator and oil plugs at rear of engine and oil filter housing)

Otherwise its normal maintenance...

 

Thank you.

I am wondering about getting the later model E350.

Currently I have an 06, with the engine that could have the balance shaft issue, so thinking about moving it on. Currently has 35,000 kilometers.
Was 11,300 when I bought it 2 years ago.

Already repaired or replaced the TCM, oil level sensor, and steering angle sensor.

Are the W212 more reliable?

Maybe there are other threads on this.

 

Yes the W212 is more reliable than the W211. I have both. Best is probably the 2016 models, last of the 302hp vs, the 2017+ started with just the 4 cylinder. Also 2016 had apple carplay/android auto, prior models didn't have that available. Or at least start with a 2012+ model, those came with the newer engine from 2012-2016.

 

Thank you.
I think the one the dealer has coming is 2011.

But it might also be a 550.
I am waiting for confirmation before I even consider changing.

 

The M273 in the E550 has the same issue with the intake manifold. Basically oil gets in and gums up the flaps. Changing the oil separator/cover may help but it's a tad under 1k to change out the intake, got mine done at an indy for around $800. The 2012+ doesn't have that issue but the spark plug change is a bit more expensive but changing the plugs is still cheaper than the intake. E550 also have the airmatic issues, E350 didn't have airmatic. I think airmatic was an option in later years, but I think it was still standard in 2011 on the e550.

 

Thank you.
I really appreciate your time and comments.

I have read about the inlet manifold issue, I think it also applies to my car.

Given the many different versions of MBs it is a challenge to figure out which is the best option for me.

I think I prefer the 350 rather than the 500 or 550.

And the air suspension seems to have its issues.

Maybe I would be better of looking for the latest W211, or a very early W212, say 2009.

 

What country are you in? The last year of the W211 was the 2009 in the US. The W212 started in 2010. Other countries may have started sooner. Best W211 was the 2009 model year which was the last year. Best W212 was the 2016 which was also the last year. Between a 2009 and a 2010, maybe a toss up. More cosmetic issues on the early W212. I like the styling of the W211 over the W212 but the W211 has more mechanical issues. Of course with the same engine, both would have the intake issue. But early 2010 have faded wood and ripped mb-tex seat issues, W211 doesn't have that.

 

Hehe. You don't recognise my flag!
Not surprising.
Pretty much the same as Australia!

I am in NZ.

 

Well the W211 also had the fuel tank issue which was covered by a 15 year warranty in the US. I don't think those apply in other countries. W212 doesn't have that issue. So yeah, I can see you getting the W212 a year earlier than the US. Or maybe it's just a naming convention, they start selling 2010 models in the middle of 2009 in the US.