Personally I don't know what everyone is talking about.
I usually go on the 18+ nights (Thursday is 18+) (I'm not into cougars; I'm 21)
and as far as 18+ clubs go in the Scottsdale, Myst is the best. and I could sum it up for one reason it is this.
if you are 18 and want to go to a club, go to Myst. The water is FREE. if you go to Afterlife (which is in the same area) they will charge you $3 for a glass of water. WTF.