So I've been using brand name oils (mostly Pennzoil Platinum and M1) on my 2011 F150 5.0 since I bought it at 30k miles. Currently have 130k and still runs great with just a little rattle (that has been consistent since day 1). Any reason to keep paying premium prices for the brand names? Thinking about switching to Kirkland synthetic, but I do follow the IOLM which results in approximately yearly changes at around 8500 miles. From everything I can tell this oil is as good as any- but is it? I don't really want to shoot myself in the foot here when I could just as easily continue with the big brands for not much of a price difference in the long run.