A combination of Oskar van Deventer's Redi Cube and a 3x3x3 Cube. It turns nicely. Because of the centers each splitted into four parts, this puzzle shows up with some additional parity issues compared to a normal 3x3x3 cube.
Although Eric mentions lock-ups, the edge turns are quite smooth and locks don't happen too often. But careful screw adjustment is crucical. Overall the puzzle is a little bit more instable than a normal cube, because pressure on the sides during turns can move the edge pieces into a corner turn. But overall a very good design and good to handle.
Size: edge length 5.7cm (standard cube size)
External LinksTwisty Puzzles: Eric Vergo's redi 3x3http://twistypuzzles.com/forum/viewtopic.php?t=21666