For people who don't read Hyperion's official AmigaOS4 forum, I thought that I better report
my findings here:
Since Update 3, I have been finding that USB keyboard & mouse would frequently stop working, especially when using certain software (like MUI-OWB). Eventually I have tracked this down to my use of ACube's Sam440ep_setup program (in my WbStartup).
As this program only provides a tiny speed boost, you should be able to happly stop using this 3rd-party program!
So I can now say that Update 3 is ROCK SOLID for me
and I'd like to thank the whole OS4 team for it. AmigaOS4 is much nicer to use, now that I have speedy USB2.0 & corruption-free use of memory sticks.