My cube collection is small as you can see but I am always on the hunt for new cubes. So far the V-Cubes are the best. The 2x2x2, 3x3x3, and 4x4x4 all work very well. The 5x5x5 and 6x6x6 and 7x7x7 are a little stiff but a little graphite will help that out. The cubes from Rubik’s are actually not very good.