I have to agree with 02WHITEDUB.
I know a few family friends who drive MB E-Classes and it seems like everytime we talk to them their car is in the shop for some sort of repair. No such complaints from my friends who drive IS300s and RX300s.
But go drive the MB and see how you like it, if you love the car and the MB brand prestige, perhaps you won't mind the shop visits as they should be under manufacturer's warranty anyway.