I have been looking for a firewall filtered by applications, IP addresses, and service ports, for Linux Desktop. I have not tried this one yet (due to its close source), but this is exactly the kind of firewall Linux Destop users would need to fully protect their Linux PCs. Majority of the Linux firewalls filtered by only IP addresses and service ports are suitable for servers, but do not provide enough protections for Linux Desktop users.
There was an open-source firewall similar to this one, "fireflier", unfortunately it is no longer maintained. I hope someone would continue that effort.
No matter what other people says, I think the developers of Linux-Firewall.org got the right approach, and I wish them well.