My Camry really likes RLI Bio-Syn 0w-30. The motor is just as quiet today at 6,200 miles as it was at the first mile with Bio-Syn. I put in the Bio-Syn 9 months ago, and it went through the cold winter.
I like Pennzoil Platinum, too, but I heard the motor getting just a little louder after 4,000 miles with the Platinum, so I changed the PP out at 5,000 miles. I guess it's pyschological for me: if I hear the motor getting louder, I'm less likely to extend beyond 5,000 miles. With this Bio-Syn, it's so quiet, I haven't felt the urge yet to change the oil. Will change at 7,000 or 7,500 miles for sure, though, and get a UOA.