I have not driven a Prius and I do not know as much as I would like about them, but when I found my Civic HX, I spent several months looking for it, and also watching for Insights and Prii. The only Prii that I saw had two of the following: Bad traction batteries, bad transmissions, and\or salvage titles, so I would not say that the worst thing would be the transmission wearing out soon, but they do seem vulnerable.
We have kind of been discussing this in:
http://ecomodder.com/forum/showthrea...a-i-30103.html
I will not claim that the Prius is the same class as a Corolla or Civic, let alone a Yaris, Echo, or Paseo, but if you are looking for a car to save you money, the Prius would not be at the top of that list.