I think that everything is said about this site. You should definitely book tickets to Alhambra in advance. When I visited this site in June it was +36 Celsius and people waiting in a long queue. Not nice. I took my booked tickets easily from ticket machines. Area was beautiful and views to the city were amazing. Sad thing was that the Court of the Lions was still in construction. Good thing was that there were many drinking fountains in the area. And the area of Albayzin is definetely worth of visit.