IMO...Great Oil IF you can get it at a good price. Not too long ago, Amazon had a clearance on the RP, SL with Synerlec technology. They were clearing out the Gallon Jugs of RP, SL in 5w30 and 10w30 at a really GREAT price. Amazon really treated me well with a couple of Gallon Cases of 5w30 for a lot less than any of the other top shelf M1, PU, Castrol, Valvoline etc.....synthetics. I've used up most of the stash in neighbors vehicles but still have a couple of gallons left for the summer.
Now I'm running GC, 0w30, API-SL, 4 Quarts and 2 Quarts of RL, 5wt, Racing for my winter blend. What a smooth combo!