I've had a pre-facelift S204 (estate) C220 for almost 3 years now and love it, so much better than the 2001 S203 C270 we had before. Quiet, comfortable long distance car, but enough grunt when you ask for it! Only little funny I found right from the start is the slight hesitation in the transmission when pulling away from stationary in C mode - interesting first few times going for a gap onto a roundabout! Nowhere near as obvious in S mode, so I've learnt to change modes ahead of times!
Mine is Elegance trim on 16" rims. It makes the ride soft and a bit wallowy when trying to press on, so I'll be trying 17" rims soon, hope they don't firm the ride too much and make herself annoyed.
We have lots of toys - full leather (essential IMHO) heated seats (lovely in winter!), Comand, telephone pre-wire (hands free is excellent but importing contacts into Comand is a PITA), I have Comand NTG4 with only 5 digit postcode entry - doesn't bother me, as I can update with "second hand" DVD's. 2011/12 could be pre or post facelift, post facelift Comand is NTG4.5, 3 years free updates from date of first registration, after that it's 3 figures and either MB dealer or good indie with appropriate computer stuff to authorise the update.
The sort of driving you mention, I'd expect to see 45-50+ on the dash computer and best part of 600 miles between tank-ups. It will be comfortable mileage, that I'm sure of. We often do 120 miles each way, mainly motorway/dual carriageway, visiting daughter - and arrive fresh and comfy.
