It matters what type of riding you do. You see, a K&N is a paperlike material, and a UNI is foam. The UNI will block more dust from getting threw it, and also other stuff. A UNI is moreless meant to be for dirtier riding. A K&N lets more airflow threw, therefore, it lets more dirt threw. If you do a lot of muddy, dirty riding, i would recommend the UNI.
A K&N filter is also more matenence, you cannot just throw it into the sink with some some and wash it, you need special oils and cleaners to clean them correctly. With a UNI, it is much like your stock filter, throw it in the sink and wash it.
If you get the foam, UNI filter, i would recommend getting the UNI Foam Airfilter Oil though, it helps a lot.
Hope i helped :
