Should be easy answered by VLK of Pavel etc..though.
I will try it... ;)

…and I think, e.g. FU-rootkit & Vanquish (and other mentioned applications) are not viruses, but legal tools - if the user downloads them from web, it’s his own risk (and these are not really dangerous - just process hiding, …)

Can it handle rootkits packed with Armadillo or any other packer with encryption function ?
No and it's not really easy to support these packers - we support only the most popular winexec-packers: aspack/upx/... which make up the bulk of the trojans we detect.