I think that you should go with IPTables and set up your firewalls on the ports you need them only, dont let them enterfere with anything else.... also use nmap to look at open ports and close the services you dont use or need......

As far as freesco goes, its a very good firewall/router to use, especialy if you dont have much cash, just get a crappy 100MHz machine with a little bit of ram no HD or CDRom is required, just pop the floppy in, ge ta few NICs to work for your routing needs and your set