We've had it for a few months and really enjoy driving it. We purchased it as a replacement for a minivan and even though the dimensions claim to be very similar, the Flex seems a lot bigger than our extended Venture. The Flex also has the fold flat seats for all 3 rows (except driver seat, of course) which really comes in handy if you need to bring a stack of 2x4's home to build a tree fort (or something)
Size, Comfort, Usability
Although the interior is very nice, it could be less drab.