The continuous variable transmission is *extremely* smooth, moreso than a standard or automatic could ever be.
Very little engine noise compared to a regular gas engine, especially at low speeds. No high pitched whine at high speed (as with the CVT-geared Nissan Sentra 2.0 S).
I personally love hatchbacks with fold-down rear seats.
The fuel economy is great, of course, but not the primary reason for purchase (a Corolla is more economical over the life of the car).
Toyotas are great cars and Prius, in particular, has a tremendous repair record.