AirDoc is the best! K&N is good but it leaves your filter exposed to the elements (water/sand/dust) where as the Airdoc keeps your stock box but removes the restricting parts of the OE set up.
I used to run a K&N and switched to an AirDoc. For me I wanted the seal up my filter for any potential water crossings and after I switched I noticed that my engine seemed to run smoother and the air temps in the intake stayed within 10 degrees of the ambient air (when moving) where as my K&N temps would run all over the place.