PF - IPF - IPCHAINS - IPTABLES: Which makes the best firewall?

This is the discussion that needs to happen.

I am currently into IPTABLES, but I am toying with the idea of switching
to OpenBSD for one of my firewalls just to have the experience and to
implement the 'varying layer stacking' effect.

I am wondering what you guys think about the differences between the
different filtering implementations. In your opinions, which is
superior, and why?

danielrm26