Hey Peter... I've had mine about a week now.
Firstly, I don't believe Sony Ericsson have any drivers to make our Mac's work the Cradle. So that option isn't available, unless you fancy VPC?
Secondly - bluetooth. You GOT TO do it man, its really nice. I had issues with iSync and my P900, up until the 1.5 Bluetooth update from last week, since then its synced everytime. The integrated bluetooth control panel and 'Bluetooth File Exchange' are REALLY nice and simple. I tried setting Bluetooth up on a an XP machine on saturday, by contrast, it really was a nightmare.
Thirdly, Memory Stick access. For me, i've been beaming files < 5mb via bluetooth, its not too bad, typically in close range its 25kb/sec, so its not bad. Larger files, for the moment, i've been using the Memory Stick adapter, and popping it in my Camera, i too need a Media Reader.
Hope that helps mate, Bluetooth it seems, is the key!
If you get a media reader, and it turns good, please, let me know, because i need one too!
Peace