I have yet to receive my order from fasttech, since I just placed it yesterday lol. I did spend quite a bit of time looking over the website and doing some background research on the company though. This is what stood out to me. Keep in mind I was only looking at tanks and atty's, not devices or mech mods. It does not look like they are trying to put something over on anyone. Originals are marked as such, and reproductions are as well. Like others have said, the clones say "styled" They will also just give the name of the tank, not the company that originally designed it. For example, if you were looking for a Vandy Vapes Berserker tank. If it is an original the add will say "Authentic Vandy Vape Berserker RTA" or something to that effect. If it was a clone it would say "Berserker Styled RTA". There would be no mention of the company that originally designed it.
You would also be able to tell based on the price. What I noticed was the Authentic tanks actually cost more from fasttech than I could buy them from a US based retailer. Not a lot, but it seemed to be about 2-5 dollars more on average. Where as a clone is MUCH cheaper. Lets be honest, if you are looking at a tank that normally retails for 100-300 dollars and is made in Germany and the price is 17 bucks from a Chinese company it is a clone. I don't see any kind of deception there. Maybe patent or copy right infringement, but not deception to the consumer.
What fasttech will NOT do is sell you a clone for some crazy high price and try to make you believe it is an original. That being said, when you get your product it may or may not be a 1:1 clone. A 1:1 clone is where the tank and packaging will have all the markings the original product would. This really has nothing to do with fasttech since they are simply a vendor, not the company actually making the product.
I personally don't care about clones as long as the price point is in line with the product you are getting. In my opinion a lot of these high end tanks are insanely over priced. I used to run screw machines, and later worked in quality control at a machine shop. And my father in law was a machinist for 40 some years. The quality I see in some of these pieces does not warrant prices over 100 dollars. Sure they justify it by saying they bought some 600,000 dollar machine to make the parts on. Big deal, just because you spent a ton of money on a fancy machine so you didn't have to work as hard doesn't mean I am going to pay 3 times what a finished product is worth. You could get the same quality, if not better from a less expensive machine or a lathe and mill in a workshop. It would just take a bit longer to machine and might require more effort. If they bought a machine with a higher cycle rate they should be making the money up in volume, not by over inflating the price of the product. My opinion anyway lol.
Now the companies that are making 1:1 clones and trying to sell them at the same prices as the originals are wrong, and should be sued if possible.
The only bad things I have heard about fasttech are long shipping times. But that is with any Chinese company, not just fasttech. From what I can tell fasttech actually has a pretty decent warranty and customer service program.