Puppy Linux is a Independent-family Linux distribution based on Woof-CE (Debian / Ubuntu / Slackware compatible). Ultra-portable, lightning-fast OS loaded with productivity apps that runs entirely in RAM.
Strengths: Can unplug the USB flash drive after booting and keep working; Pre-loaded with lightweight office, media, and graphics software; Runs smoothly on computers from the Pentium 4 era. Trade-offs: Runs as root user by default (philosophical design difference).