I run smoothwall at work. It works very well. The interface is very easy for the newbie and as long as you have pentium or better hardware with PCI nics, the install is a snap. We have it installed on some old 486/66 machines with ISA nics, and that took us about an hour to figure out the setting and get it up and running.
I use linux router project at home, mainly because my router doesn't have a harddrive. I plan on upgrading to the Oxygen release before to long. FREESCO is very nice as well.
EDIT: As for reliability and configurability, I choose my LRP box every time. It has been running for 2 years now with a week of downtime. The week of downtime was while I moved into my new house. Iptables or for that matter ipchains give you way more control than any low end "hardware" router.
And now for the final rant. Setting up your own router gives you hands on training into what goes into securing your network. This is a good thing for everyone. With a hardware router, you really get the feeling that it is all plug and play. This is not a good thing for network security.