i have deneb and it always worked very well. at the beginning there was a dma problem due to buggy zorro3 bus, but it has been solved and since then it was very dependable also in dma mode. imho you could throw almost any useb device at it, poseidon had a class for and it worked. admittedly for me it was mostly mouse and mass storage, as probably for most other users, but there was no problems. i even used to boot from an usb stick for a while.
the problems usually been discussed on forums have been related to os4 hardware and its own stack, that were problematic afair.