Ken, I have to echo a lot of what Shawn wrote. Also preferred the '08 Odyssey on the road over the Sienna, as the Sienna felt a little boat-like. There's road noise on the Honda, but it's a trade off I took. Also ditto what Shawn said about transmissions.
Though there's no a lot of respect, Motor Trend's TV show did a van shootout last week and the Honda won. It's a redesign from the years that you're looking at, but if you decide to buy new for some reason, it might be worth looking up. The Toyota was not in the top four out of the six tested.
I don't mean to sound arrogant in saying this, but don't necessarily rule out new if a great bargain can be made. We bought our 32+K Odyssey for 23+K because the economy was down, gas prices were up (big vehicles weren't moving at all) and it was a 2008 when the 2009 had just come onto the lots. We got a moonroof, leather, etc...for $2000 more than the Chrysler dealer wanted for USED Town and Country vans that were 2 years old and with less features.
The only thing I don't like is that our previous '97 Plymouth had an absolute flat floor, whereas the Odyssey's is bumbly with seat latchpoints and uneven besides. Not an issue with seats in it, but I carry cargo and nothing slides in easy, though it'll take a sheet of plywood on the floor and some like the Hyundai and Toyota wouldn't.
Finally, wait just long enough to find out if the plave you're going to live might warrant AWD. Probably not, but you'd hate to buy a van and THEN wish you chose something different.
Consumer Reports April auto issue should be on the stands, and you can check reliability for different models at different years.
