I bought 3 of these about two months ago and have been checking them out for about 6 weeks. I thinks its an excellent alternative to the original if you need additional controllers. They're suppose to be replacement ones but mine look just like the original and even have Wii written on front and Nintendo engraved into the plastic on back. Even the silicone skin has nintendo engraved on it. So don't know what the deal is but i have found it to work just as well as the original.
If you order 3 like i did it comes even cheaper and quicker with tracking when you enable the bulkrate at checkout.
I have four 3-10 year olds and it wont bother me much of they break these controllers within a few months. For this price you can't go wrong. You get controller (probably genuine but made in overtime at the same factory), a nunchuck and a silicone sleeve.