Me? I like M1, I've used it my whole motoring life, but SM-rated 5W20 has caught up in large measure, and the M1 is so blasted expensive, I'm doing Havoline in 5W20 for the summer (at the end of my present M1 10K OCI, that is). If there's no difference for a 5-7.5 K OCI, why spend the money? I'm under warranty for 100K, anyway, might as well keep it to that. I was a 3K OCI-guy for a long time til I started reading up here, and all of it on M1.
LOVE to have all that 3K M1 back, it was just getting warmed up. Last car was easy to do the oil, this one, the car was built around the filter, so long a OCI on this car fits my sense of laziness. The filter location is a bee-otch.
M1 is great oil. Highly recommend it and will go back to 0W20 in the Winter, but for now, Havoline, with it's high flash point and Moly will work too. Wonder if Havoline is working on an 0W15 or or 0W10?