I actually really loved it here! There was a special DJ here the night I went, and it was a blast.
I barely waited in line, and the cover charge was pretty cheap ($10). Drinks were average for Scottsdale, and the bartenders were really quick. For a Saturday, the bartender that was helping me had gotten to me in less than a minute.
I didn't go upstairs, but the dance floor was fun, and the place was packed.
I loved the outdoor patio, it was perfect when my friend and I were all sweaty from dancing :). It was awesome that there was a seperate bar outside, so you didn't have to squeeze your way back inside.
Overall, I liked Myst.