I've used both filters as well ... . I believe the K&N may flow slightly more air, but I don't think you can beat one inch of oiled foam in terms of filtration efficiency. I have one of the small Amsoil "POD" air filters on my lawn tractor. The outside of this thing gets completely filty with dirt, grass, bugs,etc, but the inside is perfectly clean when I take it off the carb.
I think that the K&N is a very well made product who's main purpose is increased airflow, while essentially matching the filtration of a paper filter. When viewed in this context is does exactly what it's designed to do.
TwoSlick