I downloaded Puppy the other night at work to see what Puppy was all
about out of curiosity, and Puppy seems to be quite a robust and very
clean Live CD to run. The developer " ibiblio " has done a very nice
job. After you run the Live CD version and get your desktop / network
/ internet environment configured upon exiting (rebooting) out of
Puppy this distro will allow you to save your settings and any
installed software to a configuration file that is saved to a USB
flash drive or any hard drive on you PC without affecting the OS
loaded on you hard drive.

Puppy Live CD kernel loads to your RAM so it is very responsive.
Applications are loaded as you use them off the CD and then stay
resident in memory. So if you re-open the web browser a second time
it comes up quick
I like it over Slack. Slack is OK when you have 1 Gig or more of Ram
available, otherwise at 512 Meg or less it was unstable. DSL and Puppy
work very well with 512 Meg of RAM.
.