I have been using mine for over 6 months now with our iLive 112 and the added benefit of using the APX is that you can stream iTunes to it from wherever you are and i can also control my iTunes using my iPhone so to turn music up/down or change songs i only need to have my phone on me
my MacBook Pro is using the latest OS X (Snow Leopard) and have the latest firmware (V1.53) and have not had any troubles with it at all