Why not OpenBSD?

I was going to say let's not go there, but

Your project may have specific requirements (commercial software) that doesn't run (well) on OpenBSD

Your staff may be unfamiliar with the system (but that's fixable)

Staff familiar with a Unix typically up & running within days – and end up loving it

You don't know if your hardware is supported

Actually, common hardware generally is supported

When in doubt, do a test install on spare unit