[c-nsp] CatOS - 6.x or 8.x

[Dave Breiland]

I just acquired a client which has several 4006, 6509 (w/ SUP1), and 2948's,
all running CatOS.  Unfortunately they are all running CatOS 6.3.4 which,
among other things, has the SSH vulnerability.  I was going to just upgrade
them all to 6.4.9 but realized I could probably also upgrade them to the
latest 8.x.  I used the cisco.com feature compare and didn't see any
features I necessarily need.  However I have a few questions..

-Does 8.x provide more efficient switching, or more stability?
-Has anyone had any negative experiences performing an upgrade from 6.x to
8.x?
-Will I experience incompatibilities between 8.x and 6.x. If I have two
switches connected to each other each running one.

Thanks,
Dave