Same here... got a new Mac due to an complete hardware Issue with installed El Capitan... everything works fine exept the damn UX1... very upset. And i don't want to downgrade my whole system regarding security issues in Yosemite. But i think i'll have to.
I don't know why you guys don't develop a driver during the beta of El Capitan - or even check it out that the old one is working in the beta. Do you really have so little Mac users?