The conventional wisdom is that you can't go wrong with Lonely Planet guide, but this Brazil guide proves otherwise. The new 5th edition is little changed from the 4th, except for 1) the new Natural Brazil section. Most travelers will find this section too dry and uninteresting, while those really interested in nature will find it too superficial 2) $5.00 higher price tag.
Useful things, such as info on hotels, restaurants, entertainment, and prices are too often inaccurate. The most annoying aspect of this guide is that all prices are out of whack. LP translated prices (some of which were probably 5 years old) into US dollars when the real was 2.2 per dollar. Now it is about 3.5.
All this raises doubts of whether or not the authors actually went to Brazil to update this edition and not just slapped on a new cover and threw in a new useless section. So, if you have the 4th edition, keep using it. If not, look into buying either the Footprints or the Rough guides. The high popularity of LP is another reason to go with something else. When you go to places recommended by LP, you are very likely to run into hordes of other backpackers clutching their LP guides like bibles and afraid to make a step on their own. On a positive note, the LP guide does have useful info about Brazil's history, economy, culture, society, film and literature.