[relux]

Bluetooth PAN is very very broken on the MacBooks. You're not the only one with the issue. I havent been able to get any decent speeds with either AT&T Fuze or a Sprint Touch Pro. I've given up. I now just have the Touch Pro connected to a PC via Internet Sharing and then the connection Shared and broadcasted out through the wifi card on the PC where I can connect on the Mac via ad-hoc connection.

It has to do with the drivers for the bluetooth radio. My MacBook has a Cambridge Silicon Radio device with Apple Bluetooth Software version 2.1.6f8. Internet Sharing works great if I am using Boot Camp so i rule out the hardware. Some people have reported success using bluetooth dongles instead of the built-in bluetooth. Unfortunately, I can't verify this because both my dongles are cambridge silicon radios as well.