I’ve heard the same thing with FW vs. USB. Yes FW kicks USB in the throughput dept. But I’ve had great results from an external usb-powered Western Digital 60gig. The transfer rate is not fantastic – about 16MB/s but plenty for editing dv in the field. I’ve just cranked 3 different tv spots using just this setup while sitting comfortably in bed, at the car dealership waiting for an oil change, or at a coffee shop.
No, it doesn’t keep up with a firewire drive but since it’s usb-powered its completely portable. Now I wasn’t working in HD and it wasnt’ long-form but for short stuff without a ton of footage it works great. Multiple layers do need to be rendered but most everything plays back realtime just fine on my 15.4″ MBP Core Duo 2.16 w/2 GB ram.
I have never experienced a dropped-frame on capturing DV onto that drive.
Also, these are the type of projects where I can transfer them to and from our big MacPro system (by keeping all footage in a single folder) and finish editing there. But what a convenience to take some work with me or work on something in the field without carrying a huge heavy FW drive or looking for a power plug.
I’m not recommending this for your mainstay… you do need to keep higher performance drives but some of these usb’s are just so cheap for the occasional small-form use.
Best Buy has a 60gig on sale this Friday for $50.