Nothing. I've never had better than formula so I don't know. But again, i'm wanting to upgrade the entire wheelset mostly because I want bomb-proof dt swiss 1.2 rims.. so, this is a chance to start over with a quality hub while I'm at it. I'm only brainstorming and gathering opinions. Next I'll start adding costs, etc. Maybe I'll simply leave the formulas on and have the wheels rebuilt only w/new rims.