Silly way to compare stuff but my Arch always run with processor at 70-72 degrees Celsius. Same setup on FreeBSD and my processor runs at 39-45. Since everything else but kernel runs as exact copy it shows to me that FreeBSD either has less kernel overhead or does scheduling better.
FreeBSD's hardware support is pretty poor - they don't even support intel graphics cards from 3 years ago - https://wiki.freebsd.org/Graphics#Intel_Graphics. WiFi support can also be spotty.
A serious question, since such recommendations are regularly thrown around in these threads.
Can you run FreeBSD with a recent AMD GPU (I know that there is the proprietary NVIDIA driver)? Does Wayland work? What about HiDPI screens with GNOME? Is there support for Dropbox now? Is Chrome supported? Does it use GPU acceleration for movie playback?
(As far as I could gather the answer to most of these questions is still 'no'.)
It all depends on what you use but definitely works well for my needs.
I am using offlineimap, mutt, vdirsyncer, khal, khard, w3m, urxvt...