We decided we needed seating for 6-7, but didn't want an SUV. That left the E series and the Volvo V70. The E350 is beautiful, well-appointed and comfortable/luxurious. The suspension and steering, however, are softer than they should be, especially if you are used to driving a BMW with sports suspension (or even an Audi). The Volvo V70 R was sportier in power and handling, and had WAY better front seats (the most comfortable seats I have ever sat in, in fact), but was too stark/dark in the cockpit. Probably, upgrading to the E55 Wagon solves the problem, but for $35k more, that's insane. Come on Mercedes, make it handle more like a German driving machine!
Rear facing third row seat and automatic power liftgate.
Tighter steering, better road feel and stiffer suspension.