The new Qiyi 2x2x3 puzzle has pretty much set a new bar for cuboid puzzles in terms of quality. It's perhaps not fair to judge an older puzzle, like the Witeden 3x3x6 Cuboid puzzle, against that standard - but here were are.
Witeden has released two nearly identically-named 3x3x6 puzzles. This is the cuboid version - it's a regular 3x3x6 puzzle, with each piece being a perfect cube in shape. Essentially we have two 3x3 puzzles stacked on top of each other. Also, because of Witeden structured the axes for turning, this puzzle is able to shape shift. It looks great when you do that and can make some really cool shapes. It turns really well and feels good. It's not the same quality as a Qiyi but it's good quality. Good stuff. If you want a 3x3x6, buy this one, not the other Witeden puzzle.