I hate to be an avocate for one program alone but so far after a full year on a 2yr. license the program has outperformed any other. it's certainly well written and hasn't seen one clash with any other program such as needing to be disabled to run a game or full screen app running quietly in the background.
Originally when it was first installed I reinstalled both the free version of AVG as well as the MS Security Essentials which usually would be advised against running more then av program and no clashes seen. The active protection as well as scan results were definitely more noticable with VIPRE however. The firewall and web and filtering combined proved to be an asset as well.
The image here shows the results for a 6 month time frame.
Someone just pointed me to another comparison of several products. The first of two links is comparison between Norton and VIPRE seen at http://www.pcantivirusreviews.com/Co...rton-vs-VIPRE/
The second is a review on the Premium version. http://www.pcantivirusreviews.com/Re...tware-Premium/