The APB: Reloaded blog also mentions that the game is said to have a new ranking-system and add new spawning tweaks during the open-beta, though, some of the other new features may be added beforehand.
GamersFirst has already let a group of about 40,000 people into the beta (which is currently still in closed form), so sign-up today and see if you can play All Points Bulletin: Reloaded before the actual open-beta on May 18!