I tried valvoline, both the conv and the synthetic. I only used the synthetic for 1,500 miles or so before draining and replacing with Mobil 1 0w-30.
I left the valvoline in for the entire 3k. I liked them, but only did the synthetic because I couldn't find any mobil 1 on sale that time around, hence the drain a mere 1,500 miles later.
Overall, I liked them both. I can't really compare anything since I didn't do any UOA, but I didn't suffer any major burn off or oil loss in either car so I was happy.
This is also my first round with 0w30 AFE and I'm liking it. in the prius, the first 5 minutes which usually suck FE wise, are averaging well over 25mpg. Prior I would see mid to upper teens during that warm up time.