ME for sure. It's the only release that has been like taking a step backwards.

Firewire will always be faster than usb2 . Usb2 relies heavily on the pc, whereas firewire works independently.
Firewire will run at the 400mbps quoted, whereas usb2 will rarely run at anywhere near the theoretical maximum of 480mbps, because of bottlenecks within the pc bus.

Theres a quick comparison here:
http://www.usb-ware.com/firewire-vs-usb.htm

I always use Seagate myself. Never give me any bother.