It works fine under Knoppix - all versions. As well as with other famous Live distros too - SlackLive, SuseLive, MandrakeMove...
I've been using it for a long time with RedHat8 and a little with RedHat9...

Although I've heard not very good things about it...
The only problem I can describe is that sometimes when restarting Windouz/LINUX it seems like the card doesn't 'flush' well and is not working. Means I can't reboot from LINUX to Windouz (or reverse), but only shutdown and switch on again...
I'm not sure whether the problem is in RealTek, coz I have a bad scanner -
Umax ( And htere is a conflict sometimes...
I'm not sure, the problem may be in the MainBoard too... (VIA)...

Altoghether: A good and cheap NIC No problems under Knoppix - all versions, installed or not.