Here's what I've experienced:
Drip on LR attys - I can get a burnt taste if I don't keep it wet. The juice vapes hotter obviously so some flavors quickly taste burnt. Fruity flavors taste burnt but sometimes vanilla will taste burnt if I take too long of a drag. My TV Tobacco tastes awesome on an LR atty regardless of length of drag.
Drip on regular attys - The only time I get a burnt taste is long extended drags on lighter flavors like fruits. TV Tobacco tastes good but the flavor is not as rich as on an LR atty.
Standard cartos - I've used this method the most since I've started vaping because of convenience. Everything tastes decent, even vanilla. TV Tobacco tastes a little washed out. After a refill or two, the taste drops on any flavor and sometimes you can taste a "spit" like flavor (no doubt that's actually what it is). If they get too dry, you can definitely taste the burning filler.
LR cartos - The first always tastes good, but again, some fruity or light flavors quickly get a smoky, burnt flavor to them that is definitely not the filler. It's just the juice cooking instead of vaporizing. After one refill they start to taste nasty, again, like spit (I swear I'm not fat lipping it or drooling into the carto, I'm sure, inevitably, some gets in there though).
CE2 cartos - I won't rehash everything that's been talked about. I do get great vapor, consistent hits, smooth draws. However, on a BRAND NEW UNFILLED carto, if I take a draw on it without putting it on a battery or filling with any liquid it tastes like plastic. Like I said before, take a mcdonald's straw and chew the end of it a little and then take a drag from the straw. That's the closest description of the taste that I get, regardless of what flavor I use. The TV tobacco masks it a bit, but it's still there.
I haven't rinsed them yet or tried vinegar. I have removed the end cap and I can still taste it. Sometimes I get used to it and I don't think it's there but the second I think of it, I taste it. It's like "the game", the second I think of it, I lose.
Anyway. I'm just trying to point out, it's not the usage of the carto. It's not the liquid. It's not lack of experience in other LR or high voltage vaporizing of the liquid. It is a very distinct, very unique to this carto, taste of a plasticy chemical. Whether it's the glue, the fact that there is plastic inside of the carto or some holdover from the manufacturing process, I don't know.
But it is there, I'm not crazy so neener.
EDIT: I should point out that I use a ProVape-1 and KR-808D-1 batts with 510 adapters. The ProVape is a full 3.7v device. The KR808-D1 ar standard fair.