Most of the modern BSD distros have incredibly advanced and performant packet and networking systems compared to Linux.

Some benefits over linux (this is especially geared to openbsd):

The main reason BSDs are awesome: `pf` is an amazing firewall/routing/shaping system.

Stability: BSDs have been far more stable under heavy loads than Linux.

Security: Generally (free|open)BSD are far more proactive with security patches and fixes than Linux distros.