I've really only seen a couple around larger cities, like Boston or New York. Typically they're either just handing out booklets, & expounding on their beliefs intermittently. Others are screaming at the sky, on a crate.. but those people haven't appeared to be part of any particular church groups, or anything structured. A few of the latter appear to be homeless, or near it.
I'm not religious, but I respect those who are, and I understand they're trying to spread what they believe in to their fellow man, so I try to be patient when I encounter these people. I'm often pressed for time when I do venture out, so I don't spend much time or thought on what they've said, & can't dissect the actual belief systems/execution of spreading the word adequately. I do think some have more "people skills" than others. Public speaking & persuasion are a developed skill- maybe some don't recognize the importance of honing this. And perhaps it depends on timing, and location. People might be more receptive to street preachers around Christmastime, for example.
Either way.. I prefer them to the door-to-door religious folk. Door-to-door people, whether they're peddling religious beliefs, Comcast, lawncare, Girl Scout cookies, or political crap.. they all = Just.. instant [quiet] rage. Street preachers, I can see from a distance, and avoid.. plus they're not actively coming to my private home, invading my personal space.