RFM and MMM are quite different to use. Horses for courses - Messicks did a video on it.
An RFM can be pushed back under things. They usually rear discharge, so they spread your clippings evenly. Often they're stronger/larger. If some of the people who mow in your household aren't good at machinery, they can be hard to get into tight areas - the way they move when you turn can be counter-intuitive.
A MMM can be easier to use, you look down and it's right there, you don't accidentally swing it into things. They're usually lighter weight, and they usually side discharge. If you mow frequently I personally think side discharge is better.
How large is the area you're mowing? An RFM would be overkill on less than about an acre I'd think.