Hey ,
The reason the Media Framework does not function comparable to that of UDK is because we licensed the media software to integrate within the engine. In other words, we had to pay to have the media framework implemented. Now since Unreal Engine 4 is free, we have to create our own framework from the ground up, which is the stage we are currently on.
If you have a look at the media framework documentation, it mentions this asset is not fully production ready and has compatibility issues. If you are really adamant about getting media files to play without issues you could technically buy the media framework we used in UDK, and create a plugin or use the source code for a GitHub pull request.
Media Framework
Bink Video
With that in mind there are workarounds and certain formats in which the media framework can be more reliable, and give your greater control over the playback. If you have any further questions or concerns, or if you need assistance with a specific issue please let us know.
Thanks,