M&M lacks the ability to accept video so would need another screen...not worth it when you can just about touch the rear window from the drivers seat! ...mine has reversing sensors which are superfluous but came if you specced cruise control which I do use all the time.
I have the original in my new High Up. I was debating about getting it in such a small car, but went ahead, since I was already ticking all the boxes for extras. It is surprisingly nice. I reverse as I normally would, but it is like an extra mirror, letting you see an angle not available otherwise. I park like always, but use it to check before I start and distance to the parking lines when I am in. It has a horizontal line marking 0,4m from the rear, which you can align with parking lines. It doesn't adjust it's graphic with the steering wheel position, like bigger models, but that is really no problem the way I am using it.
I think you should consider it an extra input. If you use it as your only way of orientation, before and during reversing, I think you will become a horrible driver.
I have ordered one for my new car because reversing out of a space in a supermarket car park is quite tricky. Judging distances in a mirror is difficult, and when I twist round I cannot see the front of any car behind me so it is impossibly to judge how much further I can reverse.