First of all Internet security is not just a matter of web and application filtering. It’ a matter of network integrity where as a network administrator should guarantee 24/7/356 access to network resources internally & externally and to be able to protect your internal and DMZ networks from intrusions and attacks, the best scenario is not just to deploy ISA or Linux as firewalls. the idea is to have Web-filtering, Application Control, Anti virus, Anti-Spam, IDS and IPS.
I think we all agree on the above.
For me, am sure that Squad servers are so heavy duty servers and can serve enterprise networks easily, for ISA I hate microsoft bugs but i like the ease of use.
it’s two different worlds.
Last but not least I am using Fortigate firewalls.