Norton was a bit crappy between 2004 and 2008. Mostly because it was slow as hell and its LiveUpdate part very unreliable and prone to failure. Then, after floods of complaints they started improving it. Version 2009 was much better, followed by version 2010 which proved to be one of the best on the market with very high scores in most of tests (perfromance and detection). The corporate versions were much better even before 2009.
Very similar to McAfee's enterprise offerings which were usually far beter than consumer ones.