Hey now! VLC, the bestest fastest sweetest codec-iest easiest to usiest and every positive -est adjective there is video player around, is now available (again) on iOS. If you're looking to play videos on your iPhone and iPad, VLC is probably going to be your best bet.
MacStories spent some time with the new VLC app and though it looks pretty much the same, it's supposed to be improved:
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.
The app also lets you adjust playback speed, tweak brightness, contrast, saturation, etc. and supports subtitles.