avast! will automatically protect your machine, stopping most malware most of the time, with little or no user intervention, and come up with the occasional false positive.
In order for CIS to stop almost all malware, they haven't made it any more intelligent, what they've done is move the goal posts! - and added the D+ "sandbox" as a damage-limiting safety-net.
CIS's target area is anything that it doesn't know and trust, which includes many safe, clean & otherwise non-malicious files. Anything not on its whitelist will be stopped or "sandboxed" in partially-limited mode, which is not truly virtualized, it's just given limited system access rights.
My opinion then? If you like to spend a lot of time fiddling with your security application(s), setting permissions, manually adding items to "My Trusted Files", responding to inanely worded alerts offering a range options which though similar sounding - are clearly intended to be understood to be different, reading "leak tests" which co-rate the ability of AV products to "perform" in the same manner as a dumb firewall or HIPS, I could go on... If you trust Comodo with your OS installation - give it a go. If you like it, keep it.
