Well, it presumably goes DOWN really well. In Freediving, GETTING BACK UP is by far the most important part. I don’t like the reliance on the buoyancy bag. Just a complication that provides an opportunity for failure and catastrophe.
My assessment:
1. it goes against the essence of freediving, which is simplicity and purity (not talking about No Limits here, which is mostly an academic exercise)
2. it doesn’t look very maneuverable, so you’d probably better have your route planned out
3. the one merit it does have is no or little effort, which means much less oxygen consumption and more time at depth
4. freeing the arm is conspicuously absent from the video; probably left out because it’s a royal pain in the rear to do
5. cool idea; major points to the guys for creativity and the pioneering spirit to try new things