I've ridden PI, Assos, DeMarchi, Santini, et al.
I got Ozon I's in 08, having sustained burning abrasions with PI after 30 miles, that required me getting out of the saddle more than I wanted to.
Wow! I stocked up on several pairs, most on autumn sale. They're worth the full price, because I've paid that too, (as infrequently as possible).
You can ride all day, sitting heavy in the saddle, comfy, and the chamois pad holds up with numerous washings for multiple thousand miles. The Elastic Interface Technology pad (symbol <>") is made by Cytech, an Italian company that Assos has an ownership stake it and does design work for. The best shorts from many manufactures either use Cytech Elastic Interface Technology pads, or pay Assos for patent-use licenses to make their own EIT copycat pads, or use out-of-patent Cytech/Assos technology.
I also love a couple Assos FI.S5 Milles, their pads are a less prone to hang up on your saddle nose after climbing out-of-saddle, or starting from a dead stop, and slipping back onto your saddle without "artifically" raising your bum to make sure you clear the nose. That's the only advantage to Assos long-distance bibs over Ozons, not insignificant, it is noticeable, like if you ride Milles then switch over to Ozons, and you try a "low profile slide" to reseat yourself, you will notice, "My pad is grabbing my saddle nose!". For long, in-the-saddle comfort, Ozons are on-par with Milles. They are both uber-durable all day riding, numerous machine-wash, comfy bibs.