Assuming knockoff is a forged product (uses the very same brandname, but not authorized by that brand) or a slightly altered name to deceive (i.e. Call it Trekx instead of Trek) it would be an inferior and likely dangerous product regardless of what country the knockoff was made in.

I'm sure there are 1,000 like products and some are better than others. OP would be better served to ask about a specific one, than just asking for a blanket opinion. Same like asking if all ebay or amazon products are bad.