When you buy really cheap stuff, you often compromise quality. Many of the better clones are a bit more expensive, but still nowhere near the price of the authentics. A higher quality clone can be fantastic... often better than the authentic versions.
Authentic Samurai has janky threading. HQ clone fixes this.
Vapetech pegasus hits harder than authentic and it has deeper engravings.
Ameravape Manhattan is a pipe bomb, Ameraclone FUhattan vents properly, so the clone is a safer mod for all vapers.
Authentic Plume Veil 1.5 has horrible machining issues, HQ clone does not.
CCI Copper Tank Mod is a harder hitting single tube compared to the Authentic Copper Panzer.
Granted, this is not always the case, but in general for anyone who takes the time to research manufacturers and willing to spend somewhere around $30 to $60 can end up with some really great clones. But an $8 mod or atty from Fasttech is most likely going to be garbage.