I had Mirena put in after researching pros and cons and talking to the nurses at my OB/GYN. I decided it would be the easiest BC for me. I had been on the mini-pill for several months(same hormones as Mirena)and had no problem. The insertion wasn't bad, just a little cramping. I cramped for about 4-5 hrs. afterward but it wasn't too bad. My side affects started about 2 hrs. after insertion. They included: headache, pain down my legs (on and off), and bleeding. The next few days I had: joint pain/aching, dizziness, fatigue, moodiness, weird discharge, bloating, nausea, nervousness, pain behind my eyes, bad pains during sex. Then the acne started. I have never had an acne problem in my life. My legs were covered with acne. I had my Mirena removed and I would say it took about 2 weeks to rid my body of the side effects of this horrible device. I would not recommend it to anyone. I know a lot of people have gained a lot of weight with it too. You asked for pros too: 99.9% affective against pregnancy. I never felt like having sex anyway with this thing in. I wish I had opted for the paraguard to begin with. I know there are people who do fine with the Mirena, but there is absolutely no way to know how it is going to affect you until you get it put in. It's an experiment I wish I hadn't done!