The nice part of purchasing your car is that you can personalize as you see fit. I have not had a problem with any K&N filter on any of our vehicles, Import nor Domestic. From Cold Air, to Short Ram, and Drop-In K&N Filters, none have created any failures for us. The vehicles that I have run a non-OEM filter on are brand new up through 230k miles on the odometer, so I trust K&N.
You also need to be a responsible driver, no standing water with a cold air intake or over the hood water entries with a filter box snorkel behind the grille, so those are just a few things to be mindful of while cruising.
The longevity with any product is care and maintenance, the same theory needs to be applied to the Air Filters. The open element filters attract more, so they need to be cleaned/replaced more frequently, we do every 5k miles or six months. The Drop-In filters have a single point of restricted entry, pending any airbox modifications, so you may choose not to service the filter as frequently, we still stick to the 5k miles/6 month theory. If you do fine dirt road driving, it is worth checking and maintaining it more frequently.
The reason that so many different companies exist is simply because every engineer's opinion differs and the same holds true with car owners. You can run OEM, SPT, AEM, K&N, EL Cheapo, etc. and feel that what you have installed is simply improving the air flow for your engine.
It would be nice to see an unbiased organization do a true various particle filtration test on the above listed types and brands of filters available on the market for our Subaru.
With every part or toy that you change/add to your warrantied vehicle YOU are the one that needs to be happy with its performance or look. Data and opinions are informative to make your decision, but remember that it is your gamble replacing a factory regulated OEM part with anything NON-Authorized for your car, in our case the versatile XV.
Dan