Guys, regardless of the filter brand and typer, you should NEVER reverse blow it out with compressed air. You can blow microscopic holes in the media and your filtering will be significantly diminished.
Curious if your air filtration system (not just the element, but the whole system) is doing its job? A UOA (Used Oil Analysis) might be able to tell by measuring the amount of silica and/or aluminum in a sample of used oil.
There are lots of places that provide this service (for $20-$25). Here's one I use:
http://www.blackstone-labs.com/gas_engines.html