Its very cheap stuff. Largely below WalMart level quality.
However everything I have gotten from them is functional (including some high-tech devices)
You can get some things there that are not available in the US at all.
The prices more than compensate for the quality.
Even with my employee discount (I buy at wholesale!) I can still get some bike parts cheaper from DealExtreme.
The customer service is surprisingly good - when an order arrived with something missing, they answered my email promptly, took my word for it that it was missing, and sent out a new order (still no shipping) with the missing item.
Only drawback is the shipping takes up to several months.