I recently upgraded my Powerbook 17" and ym G4 Sawtooth tower to 10.4.3 and
installed Ardour (the tiger version of the .dmg) the 4 plugin .dmgs, JackOSX and
QJackCTL.  It works without issue.  I've run it with a MOTU 2408 and with an
Event EZBus created as an aggregate deviece.  I'd say, come on in, the water's fine.

Matthew Polashek
matt@tinysongs.com
www.tinysongs.com