I'm a bit of a Pennzoil fanboy. I had used PYB for years and years, though admittedly I have moved on to using strictly all synthetic oil. No particular reason except for it has become cheaper and cheaper to get synthetic. If the Ultra Platinum was more widely available, I'd probably strictly use that. Seeing as it's pretty hit or miss, however, I run whatever I feel in the mood for. I've gone from Ultra Platinum to my current fill of Quaker State Ultimate Durability, and my next fill (which will be in about a month or so) will be Mobil 1 AFE 0W-20.