MOV files are video container files that are commonly found when working on Mac. MOV was originally developed by Apple and is primarily used in Quicktime. In recent years an equally common multi-media video file type was developed, the MP4 (MPEG-4).  MP4s came on the scene in 2001 and were developed from the same MPEG4 specification as the MOV file type. Generally you will find MP4 files on Windows machines.  

There are some differences between the two files types. MOV files are most compatible with Apple Devices, while MP4 files are a more universal format that work well on any system, i.e. Windows, Mac OS and mobile devices.  MOV files are frequently higher in quality and larger in file size. MP4s are typically smaller, more compressed files. Most often, you will find MOV files used in professional environments due to the ability to preserve high quality playback.