Based on this two links [1][2] I think we can stop recommending TrueOS in our Handbook.
I prefer to contrast it with you before committing
[1] https://www.phoronix.com/scan.php?page=news_item&px=No-More-TrueOS
[2] https://www.ixsystems.com/community/threads/is-trueos-abandoned.82183/#post-574390