Agreed, much better. Interestingly even the largest of the systems only has 30 litres of air. When you hit cold water your minute volume can easily be over 50 litres a minute so you get very little time. Granted if you are submerged without floats your egres window is probably less, but the rebreather gives you more time if inverted, trapped and with floats. When the cylinder is empty you will get sudden frightening resistance whereas with the rebreather you merely get a progressive desire to breathe faster.
I am also concerned that it needs a 32 page user manual. My rebreather came with an A5 sheet but there is a video. There is no maintenance or filling, merely a return to manufacturer as per the life vest. The rebreather can stay on the shelf for a year, needs no cylinders and can travel on a commercial flight.
Shark now make a version with a cylinder which is designed to deal with failure to inspire before activation. Still with the spring loaded bypass valve on the mouthpiece so you can breathe through the mouthpiece on the descent and merely have to pull the ball on your mouth as you submerge.