I do everything in .MOV, I seem to remember reading some things about file formats a few months back that managed to convince me that .MOV was better than MP4.

MPEG Streamclip seems to be the always recommended program on Mac to convert video files. To keep your files to a manageable sizes select the box that says ‘Limit Data Rate’ and put a number around 8000 into the box and you should be fine with quality and file size.