Antidote is a brand that is fully behind the "raw" chocolate thing. This means the beans are not roasted before they are winnowed and conched. But, as Leila will point out to you, there is something different about raw chocolate that doesn't sit well with some. Which is why Antidote smartly mixes 50% raw chocolate with 50% roasted chocolate to balance out the flavors. I think it turns out great -- you get the interesting raw taste while staying grounded in the familiar.
Antidote's 84% "Essential" bar is nice. It is less sweet than most such bars, but I obviously have no problem with that. It didn't taste bitter to me at all. It was really an ideal vehicle for getting at the taste of raw chocolate, without being distracted by sugar or other flavors and without being overwhelmed by its different-ness.
Bottom Line: If you are looking to isolate the taste of raw chocolate without being overwhelmed, this bar is really excellent.