When this cube was released in 2009, it was the Bee's Knees. Finally, a 60 mm 4x4 with a ball-core mechanism, so all the gliding of the Meffert's 4x4, the size of Eastsheen, and half the price of either: brilliant! Of course, it's marginal success was eclipsed when shortly thereafter came the Maru 4x4, the first 4x4 to come with an adjustable screw-spring mechanism that didn't misalign every 4th turn like the original YJ's. Enough of a history lesson, on to performance:
Turning: Glides like a kite. VERY little turning resistance. That, coupled with its margin of corner-cutting at a third of a piece, and absolutely no corner cutting, the lockups that occur on this cube are simply too much for the modern cuber.
Stickers: Initially, this cube came with durable, textured stickers that refused to fade or peel, but would rather chip under certain duress. Quality aside, the shades were horrendous. Dullest stickers of any cube you'll find. The newer stickers, though, featured shades similar to that of the dayan puzzles, if not a slightly brighter yellow. These stickers, while less durable, are significantly brighter on the yellows, oranges, and red, but the green is partially darker, and the blue is a lot darker than the dull-sky blue that appeared in the original batch.
Design: This take on the original ball core offers slight improvements, such as longer edge wings to fix the crippling pops that the Rubik's and Meffert's puzzles saw, and broader center stalks to ATTEMPT to fix the breaking centers; sadly, it does not. The center stalks are rather brittle, and care should be taken when solving the puzzle, especially if using any spray lubricant like CRC (but who uses those, right?)
Verdict: This cube is great for any cuber trying to learn accurate turning, as the near uncontrollable gliding of the layers can partially remedy that issue after 200-300 solves Recommended for also collectors that enjoy cubing history. Not recommended for serious speed cubing n...