I've been searching for a lower cost, higher quality replacement air filter for quite some time now, and finally I am satisfied to say that I have found a replacement that makes the OEM filter look cheap.
For starters, let's just note a few things about the OEM engine air filter. The oem filter has oiled paper media. This is superior to dry paper in that it is better able to catch debris, however, because it is paper, it does not flow quite as well as cotton gauze media. The trade-off here is that paper simply filters better, and that is why Nissan has chosen to go with the oiled paper style media in their filters.
Now if you take a look at the OEM filter, you will notice the rubber molding process surrounding the filter, is not quite as clean as the Denso filter. Additionally, I can't say this for sure but, I believe the rubber gasket on the denso filter, is actually silicon or nitrile. Then again, I can't say the oem filter isn't using a similar gasket either.
In general, I my vote goes to the Denso hands down for better quality at lower cost while retaining the "OEM vision."
