People are mad at 'Ye this week, lol. So the opinions are going to be emotional.
He and Just are about even on solely Rocafella projects, with the beats. But I would say Kanye did better work, because College Dropout, Late Registration, Graduation, and MBDTF all dropped on the Roc and were masterpieces that he was at the helm for. Just did a lot of loosies, but he never oversaw a whole classic project on the label. Kanye was giving them back to back classics 4-5 albums in a row. He was also writing hooks and bridges for classic shyt on a lot of Hov's albums and for Beans too. I think he's Top 10 behind the boards, for that reason alone. I would have a hard time trying to fit Just in there for Top 10, all-time.
Kanye's Roc resume, which also includes his own albums, is about as accomplished as it gets for a producer. Dude was untouchable during that run.