Almost as good as K&N...
That would not be a good marketing line for AEM, True - but not good.
As for the course dust sample being used in the "control" studies, well that in itself loads the final results for efficiency toward the S&B because of the use of coarse dust. There can be no comparison unless a test is completed with coarse dust on all comparable units. The efficiency of any type of filter material will increase at all tested velocities when coarse dust is used.
An old school aircraft filter company once made this comment about "controlled laboratory tests"... I kept it around for the engineering humor....
"One of the largest laboratory considerations of prime importance is the efficiency at which the filter media collects dust. This is, of course, important because lower efficiencies generally produce greater engine wear. However, if this interpretation is to be placed on efficiency, field tests must substantiate this in all cases, and this has turned out not to be always correct. Therefore, this corollary must be tempered with judgment and substantiated with controlled field tests.
For example, if steady air flow is considered, an oil bath air cleaner may look much worse in the laboratory than on the field tests. Even with variable air flow, this may be the case. Why is this so? AC feels that the corollary is upset because the laboratory tests do not and cannot consider all of the actual variables encountered." - Field Test Speciality AC Spark Plug
Ahhhh the beauty of "independent" test data when the companies actually link the PDFs. Nearly makes me want to email Mr. John Concialdi @ AEM and ask him if he REALLY believes the marketing content contained on their home page is relationally true.
Anyways..................................... Really - Go with the K&N unit if you are going with one that will not require a tune.