Just last night I spoke with my niece's husband. He works as a mechanic with a Minneapolis Toyota Dealer. I asked him about the battery on the Prius. His response is that they get VERY few Prius' in with battery problems. The most common problem is with the brakes but overall he thinks the Prius is one of the best buys in the Toyota line. Also the batteries have a 8 year, 100,000 mile warranty and 10 year, 150,000 warranty in California.
The cost to replace the batteries on a 2012 Prius is $3,200 but it would probably be under warranty so it is somewhat irrelevant. An out of warranty replacement is now around $3,200 - $3500 BUT there is now a large after-market (junk yard) supply of batteries that can be purchased for about 1/2 to 3/4 that amount.
I asked him why he didn't have one. His response: "Because they can't pull anything." He didn't use the word "anything". He has a lot of "toys" and drives a Toyota Tundra and my niece has a Highlander.
So, when Betty's Camry finally bites the dust, I may go the route of Prius.