Been seeing commercials for a new Castrol synthetic oil called 'Edge'. Says it's got 8x better wear reduction than Mobil 1. I've used Mobil 1 for a while, since it's what Porsche recommended. I'm about to have to change the Prius oil for the first time, and I'm thinking about ordering Amsoil, but would maybe try some new synthetic if it's worth a darn and doesn't cost too much.
Did some looking around. Looks like this Edge stuff is markedly more expensive than Mobil 1. Also found some interesting info from Royal Purple that showed that under some tests, this Edge synthetic was not near as good as RP. Also some sentiments that Amsoil is still very much superior. I think I'll be going with Amsoil.