I tried Vaperesso's ceramic coils when they first came out a couple years ago. I tasted a very strong hint of what I can only describe as a type of talcum powder. I changed the coil to another one, and yep, got the same taste. The odor/flavor was strong, so strong that it dwarfed the flavor of my juice. I promptly threw them in the trash.
I think Uwell is telling the truth -- this stuff IS flaking off or else I wouldn't be tasting it. It's possible some people can't taste it (taste is genetic), but that doesn't mean it's not happening. I mean it HAS to be happening (if those ceramic molecules weren't in the vapor, I wouldn't be smelling/tasting them). As Uwell said, ceramic is essentially glass and I don't want to inhale glass.
Now we have flax paper. I think it's probably safer as it is a natural fibrous material (like cotton) with no silica or glass involved. However, the potential for "oil" being present does concern me as inhaling oil has its own set of health consequences (a serious type of pneumonia can form). I don't know if this can occur with flax paper or not, but it's something else to research.
Cotton itself may not be 100% safe, but I think at least we have a good number of years of anecdotal evidence that there's little to no harm to vapers from it. "Cotton lung" or whatever they call it seems to only be a problem for industrial workers who inhale (raw) cotton dust for 8 hours per day.
