Never been or seen an actual roundabout, they sound interesting, though I can see it also being hard to get in or out of if there's too much traffic since nobody is letting you in or out and people will beep at you if you stop.
Actually from looking at the video it seems getting out would not be hard, and as long as people get out, it should not be that hard to get in, this is even more true on bigger circles.
I say make more roundabouts, and put wind turbines in the centre. Solve two problems at once!