This is a Rubik's cube the is shape-oriented rather than color oriented for solving in the dark or for those who are without sight. It is inspired of the now unavailable "Blind Man's Cube" that was made years ago by Politechinka. See: http://www.twistypuzzles.com/cgi-bin/puzzle.cgi?pid=63&allprices=1
This cube brings a unique characteristic to solving a Rubik's cube that no other cube does... the ability to say "I solved it without even looking at it once."
Rather than building hand-eye coordination, it builds hand-mind coordination.
I find that solving this cube is a challenge above and beyond a normal rubik's cube. It takes me significantly longer to solve than a normal cube. But as a result my speedcubing times on regular cubes have dropped exponentially. Because it uses areas of my brain a normal cube do not (memory/perspective... seeing it in touch and shapes rather than eyesight and color).
It is also a bit heavier than a normal rubik's cube... helping me build muscle/speed for my speedcubing (speedcube is where you try to solve it as fast as possible.)