Even allowing for the "new car euphoria" the Sienna just performs well in almost all respects. My wife is very impressed, and to her a car is usually just a car. Great ride, lots of nice features, and the gas mileage is acceptable for a vehicle this size and weight.
Great visibility, nice stereo, seats are versatile, lots of nice little convenience features. Very quiet and more than enough power for a minivan.
The OEM Dunlop (conventional) tires are substandard for this vehicle. They are quiet by wear quickly.