For comodo it's difficult to predict how it will behave alongside other security products. Different combinations behave differently on different PCs. Sorry for the sort of rant. Vipre site isn't much informative about its proactive protection. If it's robust then you may conflicts with CF.
On my PC CF sporadically show annoying fits of "forgetting bug" but not for the entire set of rules, only for some applications.
They told me (VIPRE Support) that i can use it along with VIPRE. Thanks. "There is no conflict between the two programs because they cover completely different zones in your internet security. VIPRE may detect Comodo as a program that will conflict, but that's only because of how the detection works it doesn't actually conflict with the antivirus. Comodo Firewall would only conflict with VIPRE Internet Security".