Chrystler Town and Country, Dodge Grand Caravan or Toyota Sienna? Which Should My Mom Get?

My mom is getting a new car, but since the younger ones are still in grade school she's gonna get a minivan. She's been thinking of the Chrystler Town and Country, Toyota Sierra, or the Dodge Grand Caravan, and Whether to Lease or Buy the Car. What is the smartest decision, based around fuel economy, interior comfort/features and ride?