One problem related to side/rear glass has been reported for the 2010 Mercedes Benz E550. The most recently reported issues are listed below.
In June 2011, I was driving at about 55 mph when the windshield cracked and broke on the passenger side, in the corner, about midway between the top and the bottom. At time of the break, there was an impact sound, as if a pebble had hit the windshield, but I didn't see any object. The windshield was replaced about two weeks later. In October 2011, the windshield broke again in just about the same spot on the windshield, under the same driving conditions, this time in a different state. It just seem like an unlikely coincident. Could there be a defect in the glass?.