USB can be very finicky. That being said, I've had luck with the Tascam 122, working on KT333, KM400, KT600 Via chipsets, as well as an Intel 830M chipset. However I have not tried M-Audio's stuff, and have heard many issues with some of them.
Also, when M-Audio's now offering firewire devices for as low as $199, I no longer see the value in USB devices.
Also, Echo is coming out with FW stuff, more than likely at NAMM next month. I will probably be upgrading to that, once they come out (unless they totally suck, of course).