Which brings me to my question, can someone tell me the difference between the different BSDs?

I needed to build a gateway/router/NAT/firewall box for our radio station network. I looked to doing it on linux (cos I've almost completely converted) but found the firewall/ipmasq documentation sketchy and also found that implementations are wildly different across distros and even across different versions.

So I downloaded the ISOs for Open and FreeBSD, I initally tried to install Open on the decrepid 166 we've chosen to do the business and found the thing just wouldn't boot. It was late, so I gave Free a try, much nicer install and to top it off, the machine booted and even worked!

The security aspects of Open initally attracted me, but on delving deeper I found that a lot of busy sites are run on Free instead.

So, considering my requirements, which BSD is best?