Nothing that I know of. The built-in firewall in OS X is a front-end to ipfw. BrickHouse is also a front end to ipfw, but offers more control and functionality.
Of course, if you're a Unix guru, or can borrow one, you can get even more control from the command-line ipfw. For the average user who simply wants to surf, email and maybe host an FTP service, the built-in firewall is more than adaquete.
Symantec have a poor history with their products for Mac OS X. Norton Utilities seems to create more problems than it repairs, judging from the feedback we've been getting on the forums here.