Sorry to dig this one up, but I wanted to post a recent tcpspeed benchmark using the DENEB, a USB200M, and Genesis.
Amiga receving from PC: 1516 kB/s
PC receiving from Amiga: 1592 kB/s
On the Amiga, it's clear the USB NICs have the potential of blowing all the old Zorro cards out of the water. Looking forward to testing again when Roadshow is released.