Yes, you can add rules per application and/or let the firewall auto-decide. There's also the option of adding rules on a protocol/port basis (i.e. smtp or port 465).
To be honest this does not add any significant functions over the Windows 8 default firewall. This also has zones (private/public/domain) and application, port or protocol based rules. In combination with the possible bugs with the Avast Firewall you might encounter (search the forums), I'd say I would not recommend going internet security if the firewall is your main/only reason for switching.
If you also like the antispam and safezone features, go ahead
