Well, I knew I would eventually up here and now is the time! I'm BMW guy thru and thru but last spring my wife bought her 'dream car'...a Mercedes Wagon. She got a very respectable CPO deal on a 2015 W212 Wagon with 21k mi. She drives a LOT hauling the oldest kid to swim practice umpteen times a week. She's logged 9k mi in the first 6 months.

First oil change came due and I told her that I could do it, or she could take it in. Ultimately, I think the convenience factor won out and I ended up underneath the e350 for the first time.

a few notes from the first oil change (I will be comparing a LOT to my BMW experience):

1) The engine cover attachment setup is brilliant. Seriously. Just pops off. LOVE that.
2) My would only pull about 4.5 of the 6.9L oil capacity. The rest came thru the drain plug. I won't bother with the the extractor next time. Drain plug was too easy.
3) the car is very easy to jack up with this standard issue . Both on the front center jack point and on the rear diff.
4) the lower engine cover is a BREEZE to remove and install compared to my BMWs. Why NOT use all the same size bolts instead of 3 different types? Mercedes apparently agrees!
5) the front suspension is SCARY identical to my X5s. The I am finding that in general, the Germans do a LOT of the same things - although Mercedes with (thus far from what I gather) a bit more finesse.
6) When rotating tires, don't forget to depressurize the fronts, pump up the rears and reset the reference pressure level.
7) Many of the maintenance procedures look extremely similar to BMW, but the BMW wrenching community is MUCH more deeply established, parts are easier to get and cheaper, and there's a youtube for EVERYTHING.
8) Computer software for the late model Benz's looks a little more difficult to obtain - but will be a must.
9) On another note, the car appears to have typically hard (high-solids) German clear coat, so it responds well to an orbital polisher for removing water spots, swirls etc.

I look forward to sharing my experiences with this car with the community. I am sure plenty has changed but amazes me how many things stay the same as they were 20 years ago!