Knoppix is for the most part stable. It certainly runs winXP into the ground when it comes to stability IMO, but sure its no slackware.

Beta-software is largely stable, just isnt as stable as it could be. Also the basic stuff in there, kernel 2.4.20, gcc3.2 etc, is all stable stuff, all of which is in the latest slack release (which is stable!! .

If a new application in knoppix crashes, you can kill it and start it again without rebooting (no consolation if you lose work, but nonetheless, does show that knoppix is largely stable).

My old Slackware 8.1 machine had an uptime of over 6 months before i upgraded to Slackware 9.0

My record for knoppix was 22 days, until I had a powercut and obviously had to reboot.