as a former toyota tech, i can vouch for the Siennas, and savage is right, the AWD version chews through tires, and they are runflat which is expensive.
BUT!
you can put regular tires on it and just buy the spare tire kit (since it has run flats it doesn't come with one).
and keeping up on your tire rotations (every other oil change) helps too, which alot of people don't realize.
the new dodge caravan is absolute crap. i had to drive one back to enterprise rent a car for a customer, and this thing had more squeeks bangs and rattles than my modded and gutted 240sx.
the chevy venture is a load of shiza as well, and they don't hold up too well over the years.
i say either Sienna or Oddessey. both have stunning reputations, great resale values, and are super dependable.