It's busted as hell but I really like it. It's a simple change in the overall gameplay but having to look out for this quick popup and being rewarded with a free heavy attack is such a neat addition to the experience.
I've pretty much switched to Naramon on all frames because of it.
I haven't gotten around to play with it much yet, but yeah I quite like it so far as well. Great to have bit more depth and power too for melee.
I did have turn down the whatever effect intensity setting though, it was hard for me to see the flash on a more busy missions.