Here's a small collection of places around the Internet where folks are questioning whether the king has any clothes. Note that the prime issue in these discussions is not sbout the MAF sensor. Nor is it about whether gauze filters need to be oiled. I am aware that K&N filters and their type are easily over-oiled. I am not at all talking about the natural consequence of that when I speak against the product. I am very aware that many folks under-oil them also, and as I have said before, you can't blame K&N for that (I find it incredibe that folks could actually not know the things need to be oiled..). I have said plenty about gauze air filters elsewhere so check out the articles I gathered after only several minutes' search.
Air filter comparison
K&N's statement regarding MAF sensors
K&N's rebuttals discussed on user forums
Autoblog weighs in
Adventure Riders forum
Bob the Oil Guy on air filters