The ease in which we can setup rules easily using GUI is great! I am able t use my experience from other firewall apps (like Cisco) without learning new things here as well :). It does not have any configuration for advanced users like me who do some scripting etc too regularly :) Have used both Windows version & Linux versions so far - windows has been better if you need more granular control over traffic than what linux offers out-of-the box - otherwise there isn't much difference between them apart that one runs faster/is lighter weight when compared against another OS flavor :) We had issues such as having certain ports open but being blocked by our ISP due their NAT settings blocking those particular port numbers even though they were allowed via OpenVPN configs.