I love the *BSD UNIXes, but there are also "issues" there as well. The FreeBSD threading model does not work well with MySQL for example and you can see database problems there. I suspect Postgres on FreeBSD is more common and works rather well so you can go that route instead.
However, the original poster wanted info specifically about linux, and while a BSD UNIX is similar, there are enough differences that productivity at first might be diminished while one learns about the port system for packages as well as other differences.
I think it is a bit misleading to say that a distro like debian "opens all doors", that is not the case. And the recent OpenSSL problem not withstanding, debian is quite secure. In fact, the OpenSSL packaging issue shows that the debian security apparatus mostly works, and that the lessons learned are quickly being implemented. One must acknowledge however that this was a serious security problem on debian's side and in contrast OpenBSD has had _two_ exploits in _ten_ years. Those are some pretty sterling security credentials for OpenBSD.