I haven't had to network with it - especially across mixed platforms - but when I had F-Secure IS '05 last year, I found the firewall to be a bit light on configuration options. I would not particularly want to network with it. You could try Kerio (free) which I find very usable for networks, or perhaps Outpost (premium) which is less user-friendly but even more tweekable. Outpost Lite is free, but less feature-rich. Kerio is very similar whether you pay for it or not; you just gain host protection and web content filtering.