My wife & I flew in there several times - we used Flightline First. Had the rental car waiting out front both times. No complaints.
I think you'll get good service from any of the FBOs.
John
I was in KNEW a couple months ago for work and we used Flightline First and they did a fine job. They did have a large amount of piston powered customers too so don't think they are a jet only place. We stayed at the Marriott right downtown so there was no need for a car. We just took a cab. I don't remember what the cab fare was but I also don't recall it being outrageous.