I've got one and they are a blast, everyone I know that has shot one loved it, everyone that hated it never shot one.
https://www.youtube.com/watch?v=yFPbHygQOjYI have seen several videos on Youtube, looks like a good way to waste ammo. I own a few ARs mainly AR10s in .308, wouldn't even wanna try to attempt it with that, probably good way to loose control of your weapon plus the ammo waste part. thought about trying it with a mini 14, thought better of it.
You couldn't be more wrong about losing control of your weapon. If that is the case they probably don't need a firearm in the first place. A .45 is harder to handle than a bumpstock on a AR.