Since we have to drive over a hilly canyon road regularly, even my mechanic liked the Sienna for that reason. I would consider the Honda if I thought they had worked that one thing out, but I am sort of afraid of it. If I did buy one, I would for sure only buy the Honda with an extended warantee to forstall any tranny hassles.
the new GM mini-vans come with a lifetime powertrain warranty for as long you the original buyer owns the van. check out the Town and Country. unless you dont want american.