What's wrong with ipchains? I have it working perfectly, no problems at all.

GUI? What are you talking about? The same people develop GUI which you use in FreeBSD, same people develop other software, which is used in almost any UNIX now. GNU is everywhere and not only in Linux! Besides, how many people work on FreeBSD kernel? I bet there are more involved in Linux development.

The actual difference is the kernel and a small set of programs (those in development by *BSD teams). Other then that it's all the same.

Dynamics? Admin it, Linux is more supported and has larger user base. Any questions here? And it dynamics directly follows from this fact!

Seriousity? How about the fact that IBM takes Linux seriously, what about Oracle, Borland, Sun, others? Now tell me which of those support and do something for FreeBSD? And companies mentioned above not only support (anybody can say that), they do something. Look at IBM contribution to kernel. Kylix, Oracle for Linux... Need more? Winmodem drivers for Linux, which IBM released under GPL.

Bottom line: kazhdomu svoe!