We purchased our Sienna right after our second child was born. A mini-van for a young family is a must! The ease of getting them in and out (especially when you have one in a carrier) is worth the money alone. This (for us) is the pure car pool / soccer practice / grocery-getter / long trip vehicle. Gas mileage (especially on trips) is outstanding. There's plenty of room for luggage and several kids. Ours is nearly paid off and we'll probably keep it - when we do decide to trade.
Rides like a car - gets gas mileage like a car - has the room of a van.
The only issue we had were the brakes in the front - we've had them turned twice. Our mechanic says they were a little small for that big of a vehicle.