Our Sienna has been virtually trouble-free, and we've also experienced an accident. The Sienna did an admirable job of protecting everyone, and the ALR rear seatbelts held the kids' car seats tight during the wreck. Still, I dislike this van. I find the Sienna dreadfully uncomfortable. The front seats are mushy and offer virtually no support. The cargo space behind the third-row seat is not terribly good, and I wish the Toyota had the same disappearing third-row seat as the Honda does.
V6 engine refinement and power
Fold-flat third-row seat
More front leg room
Improved front seat comfort
Move the radio up off of the floor
Tidy up the suspension, make the van feel better connected to the road