When you jailbreak using the latest exploit – Jailbreakme.com or Redsn0w – you only get one third-party app store installed: Cydia. RockApp is basically the Ford to Cydia’s General Motors, doing much the same thing, but a little differently. It contains a lot of software you simply can’t get from Cydia, and even has a better interface. Apps typically cost more money, but every single one comes with a free trial, so you can make sure it’s worth purchasing before breaking out the credit card. Plus its a lot faster then the older Cydia. But There is also something Cydia can do this cant. But over all this is something good to have on all jailbroken iDevices.