Fischer wrotethe first change was platform from Ubuntu to Debian. Debian-compliant packages and Filesystem Hierarchy Standard (FHS) compliance were two things that fed into this decision: “What this means is that instead of having to navigate through the /pentest tree, you will be able to call any tool from anywhere on the system as every application is included in the system path.”
and they have more than 300 penetration testing tools, I'm not too impressed though, i'm not impressed with backtrack either, for me backtrack is nothing more than an ubuntu with metasploit installed, maybe i didn't know how to use backtrack, that is a possibility, but every time i wanted to use backtrack, what i was using is just metasploit, so i ended up uninstalling backtrack and installing metasploit
I assure you it's more than just metasploit, though most of the tools on BT can be installed on most Linux (some can be used on windows) platforms.