Different people have varying opinions on it. Some think any support of a clone, which basically steals the design, harms those who create the designs. Others think it's ok to buy a clone to check it out and if they like it they purchase the authentic to support the original maker. Others don't care one way or the other.
Personally I see both sides, if I create something I wouldn't want it stolen. Then again there's only so many ways a tank/deck can differ, they all have a 510 pin, they're all based on some sort of 2 pole design (pos and neg), they all use a screw or clamp to hold the wires. Basic concept of 'rda' or 'atty' calls for what makes it function.
If someone can make a metal deck with a pos and neg pole and profit selling it for $15 I'd venture to say the person selling it for $90 is high on their own supply. I know, people will refer to them as artists etc. It's got to be one of the most simple machined mechanisms ever, after the basic concept came out to connect a coiled wire between two posts to heat it up the rest is just derivative works at best. Maybe I'm just brutally honest, but I wouldn't take a hunk of common wood, drill a single hole in it haphazardly as a single atty stand then charge $40 for it.
As with anything, some clones are good quality, others suck. True of 'authentic' versions as well. I don't have any personal experience with that style, clone or authentic so can't comment as far as that goes.
