I've taken K&N filters out of two Goldwings I owned. After one cleaning I could hold the filter up to the sky and see little bright spots. Indicates to me that some of the fibers have gone or stuck together. The only way an air filter can breath better than another one would be by having larger pores to pass air which means larger particles. Cleaning a filter isn't going to be perfect so each time it's done the filter is likely to be less effective. Personally I prefer the OEM paper type filters, they usually have more filter area and pass smaller particles.
I did use K&N air filters on my amateur float plane because of water spray. The oiled media holds up better than paper when directly exposed to spray. I use K&N oil filters on my GT. They are good filters and have a hex knob on the bottom which makes the easier to remove and replace.
