I also like K&N, have had good luck when installed in the Jeep.
I'm sure others make filters as good, perhaps even better. I tried K&N and it worked. No need/desire to try any others right now. Besides, I wouldn't want to spend the money on other products that may not work as well.
I also like the idea that I can retain most of the stock look!
In any case, most aftermarket filters will probably be an improvement over stock.