I've bought a Prometheus for my A3k a couple of months ago - but after discovering I had a dead Voodoo3 and getting another one, I actually haven't got around to installing it yet...
There are
drivers for a RTL8139 100BaseTx NIC I already have (not much point for speed anyway), but obviously I haven't tried them on my Prometheus yet. Quite a few drivers on that page, too, so take a look.
Oops - seems Matay has quit; I don't understand any Polish, but I guess the pix's name says most of it:

:-(