APF is a policy based iptables firewall system designed for ease of use and
configuration. It employs a subset of features to satisfy the veteran
Linux user and the novice alike. Packaged in tar.gz and RPM formats, APF is
ideal for deployment in any linux server environment.
so its uses iptables for the actual firewall part, like most linux firewalls (or was it all?)
seems good enough, but for most people even a simple firewall is good enough .. this one certainly likes to block things .. so it should be good for lots of uses