An interesting thing with China is that factories manufacturing stuff will often make more than they are contracted to make, charge all the costs tot he client, then sell the "excess" to make more profit for the manufacturing company.
In these cases you can get high quality goods, with identical packaging for very low prices (I have some iPod earphones that cost me about $2). In these cases you're likely to get the same quality as dictated by the original customer.
However you'll find lots of knock-off devices where the design and/or manufacture are very poor. When you consider that in most cases these companies don't have to worry about returns, quality is not really their concern.
I have a friend who runs a business selling stuff made in China. If he detects manufacturing flaws he has to pay for return freight for the items. Frequently even the one-way freight is a large proportion of the wholesale price, so it is rarely economic to return goods.
A very strong case of Caveat Emptor.