I'd imagine it's like anything else, it's a roll of the dice with mods. Best to pay attention but then that's any mech mod. All safety is down to you. You'd expect that authentic with a well known name would want to pay extra attention to protect their status and not ruin their rep. Then again mistakes happen. $20 for a clone, $400 for an authentic but the authentic still doesn't come with vaper's insurance. Shit goes sideways, you blow your face off - well sorry bout that. Some may feel overly thrilled about their clone but I see people do that with overpriced stuff as well. They have a hard time admitting when they pump all that money into something and yet it wasn't magical.
Case in point, let smok have a screwed up mod. Oh my god it's smok, what a piece of shit, fuck smok. Their warranty sucks ass. Compared to a DNA mod when it screws up. Oh well, you know, you can't make them perfect every time. I'm sure it was an honest mistake, no really, this never happens. Oh is the warranty taking awhile? Well they're busy, they're trying their bestest. People make excuses when they dump their entire wallet on stuff.
It's been proven there's a psychological effect of branding and appearance of 'quality' as well as higher price. They've done it with wine multiple times and people taste the cheap shit in a box, turn their nose up at it. They love the expensive stuff in the fancy bottle with a higher price tag, then it's revealed it's the same wine. Retail does it all the time as a known marketing ploy and because it works they actually hike prices. You'd think a 'sale' tag would sell more product but if something is too cheap people perceive it to be 'cheap' and avoid it.
Armageddon got in some hot water when it turned out some of their stuff is made in China and so many were led to believe they're all made in the US. Oops. As for things like shoes, I've had cheap walmart offbrand work boots that lasted years in heavy work environments and held up to solvents, chemicals, grease and oils no problem. I've also had top dollar nike's which were absolute pieces of shit and the sole fell off both the original pair and the replacement pair. Couldn't even get 3mo out of 2 pair of nike air.
As others said you may run into issues of cheap magnets. Threading might not be as smooth, but then you're not paying anywhere near authentic prices. So long as threads are workable and if you check the magnets or replace with better ones, there's some things you can do to improve where they cheaped out and still come out ahead. Much like Mooch's testing to find out if copper vs brass vs whatever actually 'hits harder' or has any significant voltage drop like urban legends claim. Some metals do, some don't. It doesn't mean I think all authentics are garbage, only buy clones. Not at all. Just keep in mind for some authentics you're paying an extra $50 for quality and another $100-200 on top of that for them to blow smoke up your ass. It's a good idea to disassemble any mod and double check everything, all the threading, contacts, switch function etc because you'll always be the last check on your own safety.
If you've got the time or are interested, maybe check Mooch's 'minding your mechs' series. I haven't watched all of them so can't say for sure all of his findings. He's gone to great lengths to check for things like voltage drop among various mods and their materials.