Minivan: 7 or 8 seats, which one do you prefer/find practical?

In the market for a minivan: 1st Sienna, 2nd Odyssey, and distant 3rd Routan only has 7seats. A major point is seating: 8 gets more bang for buck but with two toddlers, the middle row can only handle their 2-car seats (the center 8th seat) would be a tight squeeze. The 7-seater gets the nice pair of bucket seats in the 2nd row (apparant spaciousness) but we're a total family of 8, incl gpa/gma/uncles. So someone get's left behind. Your thoughts/experience appreciated.