Well you say that but...
The one that comes with the iPad
you don't have to convert anything
I came to this forum looking for an MP4 player because when I download an MP4 file from a website Safari, asks me which app I want to use to open it. This implies that there is not a standard app for doing this otherwise it should 'just do it'
So, the built-in Video player won't open it because it is not one of the options offered by the OS when I click the Open With button. When I click the Open With button, the options offered are
Open with Evernote or Dropbox
I am also offered the option to open in VLC but that app is rubbish on the iPad. It opens and then does nothing, hence I want another app to play the MP4 file I have downloaded. For reasons best know to Apple, I can't just open the MP4 file using iTunes as I can on my Mac. I can't even open M3 files from Safari. Can't understand why they have done this and it is the type of thing which prevents potential switchers from switching I.E. Apple have created a brilliant device and then crippled it by limiting its functionality