If I was from Tempe, I would probably call this place "Cartel's sophisticated older sister."
But I'm not.
And my background in fact has me comparing this to a little shop in my old Sommerville neighborhood. But that means nothing to you.
So...I think that Lux pretty closely approximates the coffee shop in my dream brain before I knew such a place really existed. Smooth couches, DJ in the back, study-worthy space calmly mingled with socializing circles, and excellent coffee and baked goods.
Neither mass-produced nor high on its own individuality. Just mellow.