At first glance it's impressive. Gotta give them some credit for creativity. But, once you start actually visualizing it on your desk while you do your daily work or gaming, it doens't seem so great. Accidents happen... Cords get pulled - mice go flying. This dinky thing doesn't look durable at all. My husbands Naga falls at least once a month.
Being able to adjust the size may seem like a great idea; however, at the same time it's not. It's not hard to find a "comfy" mouse. Mice with all these nooks and such definitely get dirty easy - so unless you don't take care of your equipment then this mouse style would easily become an issue.
Just about the only thing I can come to a positive conclusion about is the holes on the palm surface. Now mice aren't anywhere near as bad as when folks play with playstation or xbox controllers... and my palms don't always get sweaty when I'm casually playing, but when I get into a challenging situation i.e. heroic raid, they tend to need some air flow.