I think the question itself is too broad. Except for personal encounters with the police, our perceptions of the police for the entire U.S. come from what we see/hear in the media, what we've heard our friends tell us, and from unconsciously absorbing views of the police from what we see on television dramas. The media tend to report the extremes because those are exciting and draw an audience. Stories of extraordinary bravery or of extraordinary abuse, or what is perceived as abuse, make interesting stories, but they don't inform us about police behavior as a whole. If a friend tells you about his/her negative encounter with the police, the story may or may not be distorted by his/her personal stake in the situation. People don't like being confronted with the wrongness of their own behavior. On television shows, the person who is arrested is almost always guilty, and we may have even seen him/her commit the crime, but real life doesn't present such certainties.
I can say that on the whole, my interactions with the police have been positive, but I've never committed a felony or been accused of one. I've always been guilty of the traffic violations for which I was pulled over, and I've always been taken seriously when I report a crime. In the few arrests I've seen, the perpetrator offered no resistance and the police weren't rough with them. That's all I can say for sure.