K&N oil filter has a tad better micron count i believe, not positive you would have to look at the data spec sheet on it and compare. For the cost and availability I use a wix, or fram TG, and you are changing your oil every 3K, as long as you are religious on your oil change I see no advantage of running a K&N oil filter.
The biggest advantage with the K&N air filter is it is reusable. So you are not spending 10 bucks extra every time you change your air filter. For 50 bucks its nice knowing you will never have to change your air filter again, just pick up a cleaning and oil set for 15 and you will never be without an air filter or a way to clean it. Just be careful when putting the new oil on the filter, you do not want to add too much oil. Just a very light coat.
DJ