If your car is of the most recent makeyear form say '99 I would opt for the new Mobil 1 0W-40 for year round use. Onr grade, no hassle.
However, on slighly older MB, say pre-'99, I prefer to use 10w30 synthetic in winter as I am afraid the thin 5w or 0w may drain through the non-return check valve in the engine oil passageways. And that engine tolerance on these older designs may not like the ultra th
I use Mobil 1 15w-50 for hard summer driving for our '97 C280 as advised by a fellow who started off in MB in Germany 20years ago. Uses a bit more petrol but it is a price I pay for peace of mind.