M4A is AAC in Apple's favorite outfit: the audio-only MP4 your iPhone speaks natively. It was born in 2003, popularized by Apple's iTunes Store, and its real weak spot is older Windows software and stubborn car stereos that expect a .mp3.
MOV is Apple's homebody: gorgeous on a Mac, awkward everywhere else. The QuickTime container; often H.264 or HEVC, sometimes heavyweight editing codecs like ProRes. That makes it the right destination when what you need is shooting and editing on Apple hardware, where it's the native tongue.