Cocoa trivia: I recently had the opportunity to visit a cacao plantation (one of the few in the US). The cacao 'bean' grows inside a pod that looks a bit like a delicata squash. When eaten raw (directly out of the pod) they're not particularly bitter, have a hint of citrus flavor and a very strong taste of chocolate (d'oh).
If I had a choice between these and any kind of sweetened chocolate I'd go for the bean every time.
If you ever get to Kauai, don't miss visiting.
Also: one issue with cacao is that the 'tree' the pods grow on will take up any metals in the soil - and those end up in the beans. Cadmium is a particular problem for cacao grown in South America (high soil content). If you don't see certification that the cacao you're buying is low in cadmium, there's potentially a problem. I have yet to see chocolate with any note about being cadmium free. Not an issue for milk chocolate of course as there's so little cacao in it.
There's also a potential issue with the 'dutching' (high heat) process creating acrylamide (a known carcinogen). It's only trace amounts, but I make a point of using cacao (undutched) rather than cocoa.