I considered an R350 about a year ago or so. There were some troubling teething issues at the time, most notably the rear liftgate (not a deal breaker for me) and the 7-speed tranny (more important). I decided to pass, but may consider one again in the future.

In the model I test drove with my family, the 2nd-row didn't fold flat. The newer versions have 3 seating positions in the 2nd row; I don't know if those seats fold flat, but I don't see how they would.

Overall, I really really liked the vehicle but was put off by all the tranny issues I was reading about.

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280