Of course the quality is not as good as a lab. But if your buying undergroud labs you don't know what the quality is. As far as orals go quality would depend on the powder. My sources says 98.5% purity. And my china source is probably the same that underground labs use. So as far as orals go quality is the same.
Now injectibles are not going to be the same. My lab may not be as sterile. But if you filter the product straight into a sterile vial you are going to have a sterile product. To determine how it compares would require a lab test.
It would be an interesting comparison, don't you think.