Yeah, i've heard about that Brio4K too, but it seems like the 4K Resolution is way to hungry at this Time! Also keep in Mind, you're locked at 30Hz / FPS, which means, the Picture overall is really not that smooth, like when you're operating with a 60Hz Resolution!
Most Game-Streamers are streaming with 720p, because it's definitly enough for streaming, the Picture is good and for a Viewer, 60Hz are way more enjoyable...
... Plus, the Price Tag is just ridiculous at this moment, but that's just my point of view! :-)