War zones? No, it's not that bad. Unless that one week where the PCC (Capital's First Command) decided to torch a few buses and shoot some cop stations... It was great to drive your car through those avenues where you would usually spend one hour in 10 minutes... Our media is a sensationalist pile of BS, international networks probably base their news on our networks, so you only get the cherry on top of the cream.
Other than that, yes, Brazil doesn't treat its lower classes of society well, but if you are middle class and above, you'll find it quite comfortable here. And the anti-US feeling is pretty strong, but I'm positive that it's more of jealousy rather than the historical reasons (support of two decades of military oppression, etc) that would at least give these feelings authenticity. I for one like the US, and while I do believe that a large portion of US citizens are ignorant, I know that even a large portion of Brazilian are equally stupid if not worse (US education system is not all that great, but it's still years ahead of the shit they're teaching on most schools here).
To tell you the truth, I feel a bit of shame when someone from the same country I was born starts to defecate through their mouths (or better, fingers) on the Internet. It's one of those /facepalm moments, unfortunately this happens often.