Apple users consistently complain about the rules and limitations it forces on it’s users and app developers. Applications can freely be submitted but they undergo strict investigation in-order to actually make it onto the app store. Many apps have been denied for reasons we’ll never know. 
Flash has been a big issue with Apple and many application developers have introduced flash to html5 conversion apps. Now that the iPhone 4 has been jailbroken, many users are going that route in-order to add third-party tweaks to get Flash working.
Apple also puts the hurt on various video extensions, instead offering more support for common file types like .mov and .wmv. CineXPlayer is a new application that offers the ability to play Xvid videos without the hassle of having it convert to mp4 in the background. CineXPlayer works like any other video player, although it doesn’t look as fancy as Apple native iPad video player, it gets the job done for Xvid file types.