Not even close to Linux + Grsecurity even if all in-progress features are completed.
The security overview looks interesting.
Didn’t realize that MacOS and iOS were derivatives of BSD.
However, I’m sure Joanna (Qubes) would say: “Based on a monolithic kernel and thus in-depth defence is not possible.”
That said, it is forked from FreeBSD which is very popular according to Distrowatch, large package selection (20,000+) and a host of fanbois who state it is the best thing since sliced bread. I also see schneier groupies rave about it (BSD) from time to time if that counts for anything…