I had problems w/ USB early on and having the 1394 available was a lifesaver a couple of times. USB has matured, as debro says, and I haven't had problems in a long time. However, I now also have a camera, a scanner and pen drives attached to my USB slots. The 1394 has come in handy when the "safely remove hardware" said no and I couldn't detach w/out rebooting. I'd rather reboot than get coasters, tho.
I haven't had any problems w/ 1394 on 2 win2k & 2 xinxp systems with 4 ext HDs [3 WD & 1 LaCie] - but I think a HD is a different animal than an optical drive. I've had nothing but problems trying to burn cds then dvds, internal or ext. ODD, and I'm only burning data discs. No audio and no video.
It appears the licensing fee for firewire at a critical time restricted its availability/use & that would impact on its development. I'm not technically savvy enough to figure out if 1394 is less suited for optical burning than usb, less suited for optical burning on a pc, no one got the bugs out because everyone was using usb, or they got the bugs out but no one noticed because everyone's using usb.
Since there are no glowing praises for 1394 ODDs, I won't hold out for that option if reviews, price, or other options favor a usb-only ext. ODD.
Thanks to everyone for sharing their experience.