I don't think Toyota's authorized anything other than Toyota ATF WS. They caution against using anything else, using the word "damage".
I have not done the fluid change yet. It gets very cold where I live and so I rather wait for warmer temps to do it. But I should have had it done already when I got the stuff to do it and the temp was good, just had other things to do. I have front wheel hubs I have not put on yet either. I saw a review online from someone with a prius who used it with no problems and I also contacted Valvoline to make sure it was safe and they said it is safe to use on a prius.
