What is the best OS linux based??

It's all about your needs. Most of Linux OS provides common facilities & including some unlike features. You have to choose according to your needs...like BackTrack is best for security, you can use Fedora if you have a very good hand on Linux. Likewise you can choose Ubuntu if you are a beginner, if you are looking for a server the RedHat is very comfortable and so on & as wall as you can choose Desktop environment too . There are other many popular Linux OS' available like Open SUSE, PCLinux OS, mint etc.

hi men! look at men! the first is GNU/LINUX and the best for me is ubuntu becose you can find very software, and very documentation, you know!!! thas is very important!! good day men!!