The new thing in the car world is to be completely against K&N and all wet oiled filters. Their argument is the oiled filters flow less, cost more and coat/ruin Mass air flow sensors. I've been buying K&N for 25 years and I've never had any of those issues. I have on a couple occasions seen them over oiled out of the box and I've never seen a user not over oil them after they serviced them, themselves.
Another argument against most CAI Kits is that many draw in Hot air from the engine. That could be true, again I've never noticed a difference and all my years on Dyno's never yielded anything substantial from any CAI kit I've used or tuned. (Also, dyno's aren't real world and I get that.) :0)
These days, I usually stick with a Drop in replacement filter; either Wix's Dry premium or the K&N. Wix are a fraction of the K&N cost but they're perishable.
My F-150 has a K&N but it's also factory routed through the fender. My wife's '16 Maxima and old BMW have and had Wix. My race car had a K&N.
MPG and throttle response are both big selling features of expensive CAI kits and results are usually predicted by the Driver's habits. As a kid, I once had a CAI on a econo car and my MPG went down because I was driving by sound. Which usually made me drive more aggressively. A lot of CAI kits do away with the sound chamber baffles that lessen the turbulence and sound from the incoming air.
All points are valid fore and against, lol. I just buy what I buy. :)