That's strange...my band uses a Firewire Digi 002 with a 2003 PowerBook at live shows - around 30 a year - and not once has has it let us down....rock solid reliability.I have two M-Audio Firewire ProjectMix I/O's and M-Audio still can't get the firewire to behave. Crashing when hot-swapping (so don't), crackles when turning on a second firewire device. M-Audio are very good at what they do but yes, they made a mistake going with firewire. It's worse than useless.
In fact the only time I had problems with a Firewire interface was when I was recording with a Digi 002 through an upgraded 1.4GHz Sawtooth G4 with 1.25 GB of ram...running 20 tracks with 26 plug ins in Panther...and recording onto a Firewire hard drive. But that was more a CPU load issue than Firewire.
Also... my band's recent EP was recorded at Smart Studios in Madison, WI, you know, where little gems like Nirvana's Nevermind and Smashing Pumpkins' Gish are on the resume...and our entire session was recorded direct to a $100 Western Digital Firewire drive.
But yeah, worse than useless.