When you are running in dusty areas you always want the most effective filter you can get and monitor it closely. I have 3 of the Amsoil round filters in my basement and they re reusable. They are $25 each NIB and can be washed out with soap & water. For the oil youu can use the K&N oil for them. Dave & SashaDisclaimer:
I've run everything from sand to pummy dust, so my views may are skewed towards the worst case scenario.
IMHIO, Gauze filters (like the K&N) have no real advantage on gas engines. Gas engines don't draw enough flow at anything but high RPM WOT to see an advantage of gauze over a paper element. Being able to toss the paper element instead of servicing the gauze filter is a major advantage that outweighs the "cool factor" for me.
Diesels are another thing. They draw as much at idle as most gas motors at WOT. Their breathing needs are much more substantial. This is where the gauze filter makes it's money. Unfortunately, the engine pulls so much air that it tends to "open" up the gauze and let fine grit pass (personal experience talking here). So much of the touted advantages of the filter have been negated by it's inability to filter properly. The big intake upgrade for pre 04 Powerstrokes is the "Tymar" upgrade, which consists of a large paper filter mounted on the fender in lieu of a any of the gauze elements and/or their "cold air" intakes.
I run gauze on my quads. They only see sand which is a course medium and coupled with a sand sock, rarely need servicing. Since the stock filters were a foam oil filter anyway, the ease of servicing the former makes it a better choice for me with no loss of filtration.
A quick note on stock style air filter housings. The single funnel intake actually aids in keeping your filter cleaner longer. As the air is brought in, it picks up velocity as it runs down the snorkel. the heavier particles will tend to continue on and hit the filter in front, keeping the rest of the element cleaner. I prefer these to the open performance style housings, especially in dirtier environments, which tend to drew outside air in around the diameter of the filter.