The only caveat with FreeBSD's implementation of PF is that it's now effectively been forked but hasn't been appropriately renamed. They're still using OpenBSD

The only caveat with FreeBSD's implementation of PF is that it's now effectively been forked but hasn't been appropriately renamed. They're still using OpenBSD 4.6 and earlier configuration syntax, and have added some non-portable SMP functionality. FreeBSD PF and OpenBSD PF will be unlikely to share much if any code moving forward.