Zach,
There is a difference from this video, and the "test" your friend Eric did.
This video directly followed on the same day, whereas, Eric's test was a week of this then that test. There are may variables that can come into play from the amount of traffic to the relative humidity.
I know you were trying to put me in my place, but in this case the Kirby is a direct air machine with greater airflow. And yes, I admit, read my screen name I am biased and admit it. But I have been in the homes when Ladies have cried, not with a dirt pad that is roughly what six square inches which takes approximately a teaspoon of dirt to look full. This was done with a full size Baird meter and it was full.
Also, I stated that I was in agreement with Brandon that no machine (Including Kirby) was 100% effective.
Do the sand test yourself. Go out to the sandbox, or if not available take a pound of plain table salt. Pour it into the carpet. Now you have a measurable amount of what went in. Now run each vacuum and see how much each pulls out. Again this is able to be weighed and measured instead of a subjective--look at this. I again will state the Kirby will be able to hold it's own.