The Prius is in it's 3rd version which means they have worked all of the bugs out. It even has a solar panel built in to the sunroof which helps to keep the interior cool in the summer.
There are Federal and State tax credits available for the Volt which brings the $40K sticker down to around $25-30K.
I get 26 mpg in the city and 34 on the highway with my Altima. I could probably get even better mileage if I didn't drive it the way I drive my pkg car.