You thought it was controllable!? I sure didn't! Ours didn't have a brake nor was it ported, it was just a G17 with a selector, or stock G18 I guess. We had one along with a bunch of obscure, one off weapons for a demo we did for the US War College when I was at the Stryker Bde. Advanced Infantry Skills Center.
I think the Beowulf with no brake on burst was more controllable that day but that's just me. Coast Guard ended up buying these after that demo for boarding rifles and for taking out small outboard motors.
It was a lot of fun running and gunning though, you know, rushing an ambush? Rate of fire had to be like 1300rpm or thereabouts, it just burps out a mag in a second flat. I thought it worked well for that though, stitching targets from bottom R to top L while at a full sprint.
Wanted to fire an M93 and figured we'd have scored one somewhere since we already used the M9's, but that wasn't the case I guess.
Glad I got to fire it though, it was a lot of fun and it also made me realize how impractical that weapon is, so no real desire to own one, but it's a lot of fun and everyone should get to do it once.