Castrol Edge.
I noticed one of my car's engine becoming smoother and quieter when i switched from Mobil1 (not EP) to Castrol Edge, (2GR-FKS engine, on 7500mi OCI, made the switch at around 35k). This engine uses the 0w-20. I have a 5qt jug of Pennzoil platinum I'm waiting to put in after summer next year (got it because the $22 rebate), so I'll see if it's good or not.
My other car which I also made a switch from Mobil1 Euro to Castrol Euro because of BMW LL-01 certification did not have noticeable improvements, but the engine is still smooth with Castrol,
I would still put mobil1 in my car if the price is right. Heck, I just got a 6 pack from costrol today because it was 22.99 and I need something to blend with the left over castrol form my last OC.
The idea filling my garage shelf with just one brand of oil would do wonders for my OCD though...
I need to correct myself after looking at my notes( yes, I keep track of everything)
The instance I noticed my engine being quieter and smoother with Castrol Edge was when I switched over from Pennzoil Platinum. It was on Mobil1 for 2 OCIs before Pennzoil Platinum and there wasn't anything out of the ordinary throughout all of those time/OCs.
Probably why I didn't feel a difference going from M1 to Castrol on my other car.
Oil filter was consistent, new K&N PS filter each change which I bought bulk when amazon sold it for $4.xx. (my next batch are Denso filters, switched because rockauto prices and OEM quality. K&N is around $8 now)
I also want to mention something specific to my 2GR-FKS engine. This engine has what is called an Atkinson cycle that can kick in at idle which can emit a noise at , but it's not on all the time, so the noise could be one of those time that the cycle didn't turn on when I started the car.
BUT!!!!! I also notice my car driving smoother when switched to Castrol Edge.
Anyways, I'll see what happens when I put PP back in next year, I just wanted to be clear about my experience and not spread misinformation/disinformation. (Man, I take this $h^t too seriously...)
I have no problem switching between the 3 major brands to save $10 since I get satisfaction from getting a good deal. I might give Valvoline a try if the price is right.