It is actually a bit dangerous to use such software if you doesn't perform or complete the installation properly. From my personal experience, Windows seems have some trouble working with broken virtual SCSI adapter installed by such software ("broken" when the installation is not done properly).
Personally, the most robust one I've used is Alcohol 120%. DAEMONTools is not bad a choice too, but it did screw up my system once when upgrading of the virtual SCSI adapter was not properly done.
