Mouse input works, I can make brush marks. Genius tablet registers movement but no brush marks can be made when pressing down on tablet.
On OSX we're dependent on the OS and Qt working together to give us tablet events, and it seems that that doesn't work for all Genius tablets. We have some reports that some models worked somewhat, but not well. Genius tablets really are problematical devices. We might have to fork Qt's tablet code in any case, and then we might be able to start supporting Genius tablets, if there's someone with the right hardware who wants to help out with the code.