Scott I have no idea about these cards, but usb seems to me a bit too unstable.
I am using usb for a lot of devices in my offices and these are by no means stable.

As you know(since 2000) I am using a delta 1010 with the 19" rack which is no option for a laptop due to the pci card which need to be built in.
The connection goes through a special cable between the pci card and the 19" rack.

The rack is controlled by an eight channel software mixer and has all the needed options for monitoring and in/output volume/mono/stereo controls for analoge and digital connections.
Works like a charm.
I suspect that the software mixer is a simular software mixer for the mentionned cards by you.

In the mentionned options by you I would go firewire in this stage or wait till the lan cards come out.

Fred