Combining the best features from both distributions, and paying special attention to small details, this is probably the best version of either distributions to ever come out.
Based on SLAX (Slackware), BackTrack provides user modularity. This means the distribution can be easily customised by the user to include personal scripts, additional tools, customised kernels, etc.
A full list of the tools in BackTrack are available now.
You can download BackTrack now.
