Circling back to this thread...
I actually ended up getting a second XSurf because I couldn't decide which machine to put it in. So now both machines will get one

At any rate, tonight I installed one in my A2000. It's a fairly low end machine - not enough RAM to give browsing a try. I don't have a network port in that room, so I've actually got it connected to my iBook G4 using OSX's internet connection sharing. On the Amiga side, I opted for MiamiDX simply because I know how to configure it quickly. Was pinging out to the interwebs in just a few short minutes. I came extremely close to installing Roadshow - I may give that a try later on to see if I can stretch my small amount of RAM further with it.
My ultimate goal is to get Envoy working so I don't have to sneakernet files from one machine to another. Routing through the iBook may make this task impossible, but I still have some more tricks up my sleeve.
At any rate, if someone knows of any shell-based or other lightweight network speed tools I'm happy to give them a try. I'll do some download speed tests once I install the other card in my 4000T.