Can't speak to the Vegas station, but KOOL in Phoenix endures because it has remained pretty steady in what it offers. They've updated the playlist (less 60s, NO 50s, and lots of 70s), but aside from that, they've not tinkered with the overall "sound" of the station. They have excellent jocks, most of whom are well-known to the Phoenix area (Steve Goddard has been on Phoenix radio for about 30 years and is as great as ever), and they promote very well. They are a fun station to listen to, and keep the pace moving. Just good radio, the way it should be done. It should be noted they stumbled a few years ago by voice-tracking more than just overnights and used Tom Kent from 7-Midnight. That didn't go over well and they've recovered from that debacle.