VLC is the most capable, flexible and loved media player available on any platform and now any platform also includes IOS (iPhone and iPad). It was previously available but pulled because of a license incompatibility between the VLC license and the app store requirements. The team has now fixed that issue and made the app available again.
MacStories has said
VLC has been completely rewritten to use modern audio and video output modules, multi-core decoding, and support for any file type supported by VLC on the desktop. In my tests, the app was able to quickly start playing any video file that I threw at it, such as .mp4 and .mkv files.
I say download, download, download here.