ParaGard/Copper IUD

I went to a Planned Parenthood website where they had different methods of contraception explained in full from abstinence to sterilization.
The least harmful, to me, seemed to be the copper IUD's since they do not release hormones.
Does anyone have an opinion on this. Maybe some stories, or knowledge of how frequently they actually might slip out or break through the uterus?
I'm 22 and have never given birth, and I'm in a steady, monogamous, long term relationship.