Like I said in the absence of "evidence" from either side...its still up to you. Personally I am going with it for ease of maintenance but then your going to have some people who can't stand to clean the damn thing, so your back to square one with the opinion score sheet.
Bottom line is your probably not going to get any hp increase worth a damn from the change of an air filter on 90% of modern cars. It will probably be the equivalent of welding on some chrome tips to your muffler. But chrome tips look good to some people.
We keep regurgitating this K&N argument on this forum and many others and it won't be the last time. Someone will probably throw in some mathematical formulas next....