Sprinkles cupcakes are very good. They're too expensive and at peak times you'll wait for a while, but they're very tasty. Like them on Facebook and you'll get a daily secret word that will score you a free cupcake when you're in the neighborhood. The people that work there are friendly, and for as tiny of a space it is, they do a pretty good job of getting people in and moving them through a line.
I like their Red Velvet, Black & White and Milk Chocolate cupcakes, and they have some other, crazier flavor combinations if you're into that kind of thing. They have seasonal flavors and certain cupcakes which they only have on certain days, which is kinda cool. If you're into good frosting (which I am), you'll like Sprinkles a lot. The frosting is delicious.
If you're in Scottsdale and you like cupcakes, check Sprinkles out. It's fun to overpay for cupcakes (but at least they'll be good cupcakes) and get a taste of the Scottsdale tourist scene.