Some are, others not. Fasttech uses the word "style" to indicate a clone, and the word "authentic" to indicate real by the original manufacturer. I have never not gotten what I paid for from them.
I would say quality wise I have gotten MORE than I paid for even counting the two crappy items I got.
Just n the little Kayfun Monster Mini (my out and about Vape. I paid $5.43 for it and LOVE IT. I Paid $38 for a Lemo 2 that leaked, an authentic Aqua V2 that leaked, BILLOW V2 I couldn't get decent flavor from.
This little Kayfun Monster is in and out of my pocket for about 6 weeks hasn't leaked a drop.
I would say my little Monster Mini clone is easily worth $15-20 when compared to the authentic tanks and RTAs that wasn't worth bringing home.