I've only had a few bad experiences, otherwise it's been fine, and most people have been nice about everything.
A couple LDS guys, calling one another "elder", spoke with me at great length, and several times. Though never once did I let on that I bought into their ideas. I only had questions for them, and they had very few, and no sufficient answers - even though they said they'd "Take the questions back" to their superiors in the church to gain insight on how to respond several times. Nice couple of guys.
Some JWs came to the door a few times, but they were not pushy. They asked a few questions, keeping it all polite, and then left - I assumed because they saw no "in-road" to converting me.
A local church-going girl (probably 19 or 20) was out with her younger sister (probably 12 or 13) and knocked on the door. She cut right to the chase and asked if I knew where I would end up when I die. I told her I didn't think there was anything after death to be worried over. This really got her upset, and she informed me promptly that "hell" was the place I would be going. Better keep looking for someone who actually gives a crap.
A few other experiences where I don't remember the denomination or church represented - but the people were nice about it. They questioned me, and I answered honestly, from my stance as an atheist, and they never tried to take it to a personal level.
And then a few more instances where I was confronted out-of-doors. A man walked up to me on the street, commenting that I had nice dogs (I was walking them at the time). He tried a few paths in to his points, which I shut down each time with questions he couldn't answer, or refutations to his ideas. Eventually he told me to read The Bible and that I would "learn how vile you truly are." Way to captivate your audience, champ. Looking back, I should have asked him how many times that particular tactic had "worked."