The overall general perception of chocolate made from Brazilian cocoa is that it has a very direct, earthen flavour profile due to the predominance of the Amelonado-type cocoa strains. That perception may be correct on the most basic of levels; there still is a noticeable amount of regional variation.
Interestingly in the not too distant past, Brazil used to be the primary cocoa exporting nation - before the rise of Ivory Coast and Ghana and their cocoa suitable for the mass-market and the savage effects of disease with both Witches Broom and Black pod affecting the Amazonian Basin.
One of the most predominant regions is for growing cocoa in Brazil is Bahia and this is one that you are most likely to be detailed on the packaging of Brazil-origin chocolate. There is talk that some form of Criollo exists here having been transported from Venezuela via Sri Lanka. The prominent cocoa-growing region is Pará which, interestingly, was the source of the first cocoa exported into Europe in the 18th Century.
There are some great 'hot spots' for cocoa production in Brazil that break out of the typical 'Forastero/Amelonado' classification - the problem is that the available production is so small it isn't economically viable for most chocolate makers - we should have some award-winning chocolate grown & produced in Brazil coming very soon. In the mean-time you can find chocolate made with Brazilian cocoa below.