Who knows how AIS is improving? It was released two months ago, and since then only bug fixes have been released…
It is Alwil’s first firewall, their first virualization, their first behaviour shield…
I have used CIS since 3.5 (the first version, released October 2008), and it has been greatly improved since then. New features, much better AV, much “quieter”… The sandbox is new and needs improvements, both bug fixes and new features (in CIS 4.1…). 3.5 felt like a firewall + scanner. 4.0 feels more like a security suite, whatever that means…

I don't know much about KIS’s history, but Kaspersky improved its hips greatly in version 2010, according to
Proactive Security Challenge. A great, complete suite.