Want to play Smash Bros or in fact any game that supports the Wii and Wii U's Pro Controller worth a GameCube pad but don't want to buy Nintendo's own adaptor? Hori got your back.
Notice that they added Home, + and - buttons and what not to make it fully compatible with Wii U. However, they did drop the Z button and both L2 and R2 and not pressure sensitive like the original controllers. Also notice these are Wiimote attachable.
Since these are made by Hori, I am not worried about build quality. So if you still crave for your GameCube pad to play current games, I do believe these babies are a good investment.