That's where I'm stuck as well.I'm still trying to figure out where myself. Seems like prices are up, material quality is down, designs are consolidating...there's no real choice for those of us who actually put in more consideration to our filters than, "Yeah, that's fine."
I like the Ultras for multiple OCI's or on lawn equipment where I change the filter every 100 hours instead of every season like the oil. I'm not sure what a good replacement for the Ultra would be. Maybe a Napa Platinum? The Purolator offerings are way over-priced. I feel like the Boss is the closest thing, and I saw one for $27 on Amazon for the application I needed.
I like Wix too, but it's evident some of their filters are getting to be of cheaper quality too.