They are both free *nix, so they are very similar. BSD prefers the simpler versions of many of the common command line tools where the Linuxes prefer the GNU to

They are both free *nix, so they are very similar. BSD prefers the simpler versions of many of the common command line tools where the Linuxes prefer the GNU tools which tend to have more features. There will also be other small tech differences that will come into play in special cases, like ZFS being nice for fileservers. Other than the basic tech there are 2 important differences. First is the that there is one FreeBSD but there are hundreds of distributions of Linux. And among them you'll find much larger differences than between FreeBSD and the popular Linux dists. The other big difference is simply derived from the fact that Linux is more popular. It will tend to have better drivers, have more bugs worked out of the software, etc., just like any other free software out there. FreeBSDs conservative nature towards its core software more than mitigates this, but for all the peripheral software it will matter.