From what I understand it was pulled by Apple but the developers intends to correct the problems with it and re-release it once they are done addressing all the issues Apple had with it. Like mentioned, it had something to do with the similarities to the AppStore, or some perceived infringement upon it in the way it gather, accessed or handled the information from my understanding, though the details seem fuzzy. I still have the app and it still works, as well as the site being alive and well.
As for alternatives, I find AppZapp is pretty decent of the available app for aggregate iOS app tracking and price watching IMO... Sadly, I find that aside from AppShopper and AppZapp, the rest kind of suck...
Last edited by Bool Zero; 04-09-2013 at 04:36 PM..