(L) (R)
I install this firewall after using ZoneAlarm for several years. OMG! It is like having a new computer! The speed at which pages load is so much faster. Even ones wiith LOTS of images!
I used ZAAS and it was just as fast as Comodo. But bootup time was longer. What version of ZA? Zone Alarm Anti Spyware which I was using doesnt have a web shield and either does Comodo.
Also I came to CFP after years of ZA experience. As a comparison, my sistem was a turtle with ZA. CFP runs it like a Ferrari! 
aXes
The free version.
Well the free version doesn’t have the same the same protection level as the spyware version or the pro version. It doesn’t have a wen scanner and is no better then Windows firewall. ZA free should not slow down your pc at all except your boot times. Welcome scrren hangs for about 10-15 secs.