SimplePlayer

SimplePlayer is an open-source QTKit-based video player. QTKit is a framework for working with apple movie files, so support for MOV and H.264 files should be good.

The graphical user interface is very simple. There is a window where your content is played, and that is it. When you first run the application, a sample MOV file with a count-down will be played, and you can open new content from the File menu. The first file that I tried to open with this player, a 1080p MKV file froze the app, and I had to force quit it. After that, I played a less demanding AVI file, and it played fine. The app supports the new Full-screen mode introduced in OSX Lion, and you can access it by clicking on the button in the top-right corner.

SimplePlayer doesn't have a preferences window. All the settings that you can change are located on the menu. To control playback you can use your mouse or keyboard. If you click on the screen, you pause/play the content, and using the mouse scroll will slowly rewind or move your video forward.

In short, SimplePlayer seems to be able to play H.264 and AVI files just fine, but it wasn't good for playing MKV content. Anyway, I wouldn't recommend this app over MediaPlayerX, VLC or Movist, so if you have one of those, you are good to go.