NO, the site he linked us to shows the SAME, there is no disparity
No, the site he linked shows performance as 2/6, tied for last place out of the 25 products reviewed.
http://www.av-test.org/en/tests/home-user/windows-7/julaug-2013/
Exactly.
Performance can change after every engine or definition update, so unless they measure "performance" over the course of a year, it means little.
This site shows the ESET suite in 3rd out of 21 for performance.
http://www.av-comparatives.org/wp-content/uploads/2012/06/avc_per_201206_en.pdf
Granted, that was June 2012, but the site the OP linked shows ESET in
16th out of 25 during the same time period.
Some AV products are faster with web browsers, some faster with office suites, and others faster with java, or archives, or email, or...
When it comes to businesses there's much more at play, such as the management tools, number of incidents of updates causing downtime, 3rd party support, availability and quality of support from the vendor, etc.
The point is, testing methodologies play a huge role in the outcome of these tests. There's also the potential for bias. In the end you have to test several products, perhaps based on sites such as the one the OP linked to, and use what works best for your environment and wallet.