knockoff element cases

Hey,
I pre-ordered an iphone 4S and want the element case but due to its high price I am considering purchasing a chines knockoff like the following.


http://www.aliexpress.com/product-f...-Aluminium-Case-for-iphone-4-wholesalers.html

Does anybody have experience with these knockoffs? Do they compare to the authentic Element cases? If they do that would be saving a good 100 bucks!