I've used it and its definitely hit or miss. I got some virgin kinky curly and some brazillian body wave. Both have been pretty good, super fast shipping, like diabolically fast, even faster than shipping within the US. Quantity and quality were what I expected.
I do recommend BHM for research techniques, but no one over there is EVER going to give you a vendor name.
I recommend that you do a search for the product you want to buy, and then sort by the # of orders, so you get the vendors that have been purchased from a lot. Then peruse the reviews and see what people say about the hair, and that should let you sort it out. The good thing about Aliexpress is that your card is not charged until you state that the product is good quality, so you can always return things that are jacked.
HTH!