Often I wished more options as an Animator. Most most options years ago were far from optimal. Even if you find 2-3 rigs for a shot, chances are they are build differently, controls behave differently, the style is inconsistent, maybe some are lacking appeal. Another striking issue is often wrong joint placement, which can makes good posing difficult.
Since I wanted to make my reel look professional, I needed something better than offered in the internet, so I build my own rigs. I rigged a lot actually, when i worked in the game industry on RPGs, I decided to make them public, so aspiring animators, without the privilege of an animation school rigs, can work what's most important - the craft of animation.
The appeal of M_rigs is it's simplicity. There's no skinning, just smoothed shapes. I fell with simpler rigs, it's easier to look at the big picture; quality of spacing and shapes. M_rigs are not connected to licenses, once you buy them they are yours. However, you are not allowed to sell any rig or use it in any commercial form.
My goal is to have 5-6 characters by the end of the year, so there is a wide variety to mix and match rigs for your ambitious shots