As a guy who dailies Benzes (W212 Estate for me and wife has X166), get her sorted out, you'll have one of the most reliable long term cars out there.
Just one word of advice. If the Germans say maintenance is due at 60k, they mean 60. Not 61 or 65.
Do what they say, and she'll last forever. Traded one in at 465k because it needed a transmission mount, and I didn't feel like doing it.
Not loving their brand new stuff, thinking about going backwards (W211 or older) or switching brand loyalty.
That 5l is a great motor. Interior is the old quality MBTex. Solid transmission. Just service her; you're gonna love it until 500k.