So bad that I wouldn\'t put it on my worst enemy\'s computer.  It slows the system down, often locks up systems as bad as a virus, and is so invasive as to be no better than a virus. I have a longstanding hatred of this product and company goin back to my first computer business during 1986-1992 ACS-West

Ineffective against mainstream viruses even in the DOS days and will often cause more harm than the virus itself.  When I worked for Sprint the word came down from corporate that McAffee would be removed from all PCs in the company.  It continually interfered with our in-house applications and cost more in support than it saved in virus prevention.  

Until a couple of years ago if the installation or uninstallation glitched, you had to manually search for hundreds of registry entries to manually get the thing of your computer.  They do provide an unistall tool now, but save yorself the hassel and never install it in the first place.

In 2010 Intel has made a bid for McAfee - puzzling except that they do have high level profesional products that seem to work well with internet servers if highly trained professionals, usually at a price from McAfee do the installation.  I am writing an article to publish on Yahoo that has my predictions on why they have done this and which direction they will in my opinion.  This does not alter my  opinion on their PC based protection suite.