“We had a huge chunk of our engineering staff spending time improving FreeBSD as opposed to working on features and functionalities. What’s happened now with the transition to having a Debian basis, the people I used to have 90 percent of their time working on FreeBSD, they’re working on ZFS features now … That’s what I want to see; value add for everybody versus sitting around, implementing something Linux had a years ago. And trying to maintain or backport, or just deal with something that you just didn’t get out of box on FreeBSD.”
I still hold much love for FreeBSD, but this is very much indicative of my experience with it as well. The tooling in FreeBSD, specifically dtrace, bhyve, jails, and zfs was absolutely killer while Linux was still experiencing teething problems with a nonstandard myriad of half developed and documented tools. But Linux has since then matured, adopted, and standardized. And the strength of the community is second to none.
They'll be happier with Linux.