There are still some resource hogging aspects in KIS 2012, such as the indiscriminate CPU and RAM usage during the not so fast scans. Checking changed executables also seems to be taking rather excessive time. But it's hard not to be impressed by the comprehensiveness of its features and the wealth and granularity of the available options, the strong Web Protection and impressive Application Control.
You don't get a second chance at making a good first impression and Norton does exactly that. The easiest and fastest installation process by far, and that's just the start, setting the tone for the outstanding experience that follows - it's streamlined and efficient in providing protection, nimble, unobtrusive and responsible power.
The interaction with Norton is so effortless, it's really easy to overlook and not appreciate all the hard work that went into it and take it for granted. And quite possibly, one of the reasons why I vote for Kaspersky - not as accomplished, more idiosyncratic, but excellent nevertheless.