I backed Prime, and was a long time fan of Cortex Plus before that. My first game as a player here, and the system that brought me to Gamersplane, was Cortex system.
I kind of hate hyping Prime like this, cuz the Kickstarter was a mismanaged-at-best, or even purposefully exploitative, joke... BUT...
It's probably my favorite "tool box" system. Once you learn it's ins and outs, and how you can relabel and tweak the different "knobs and dials" that it gives you to craft a different feel for a different setting, it is just incredibly powerful, and fast, and flexible, and you can literally create a pretty customized level of crunch and unique feel for your own unique (or an already established IP) setting, with relative ease.
Under the three different Cortex Plus models (which Prime is just a unified version of) one could probably hack up a custom setting in 30 minutes or less.
It's a very narrative focused system, with a range of crunch from "Fate-like" (minimal) to probably Savage Worlds-esque or D&D 5E (mid-range).