Prospect Heights has already taken off both in price and demand. It may still have a few rough spots--but by Spring 2013 these areas will be smoothed out--Crown Heights and Bed-Stuy are getting the spillovers from these established neighborhoods.
Prospect Heights is already seeing awesome appreciation over the last 10 years. The location is right, the conveniences are right, and the future looks very good for this neighborhood - heck it's good now. The "next" park slope is pretty funny - Do you want no parking and horrible street cleaning schedule? ha ha ha... just kidding.