Everyone I know has been happy with the Mirena except for me. I am having it taken out tomorrow. The first 4 months were great. Then, it changed. I now have periods that last 1-1/2 weeks, I have cramps 3 days before they start and the first week during my period. I have constant headaches and I'm dizzy a lot. I also have not been able to lose weight. None of this has ever been normal for me.
I'm not telling you the above to scare you. From what I can tell, most love it. But, there are those of us who have terrible problems with it - mine are mild compared to others. We are the minority. Unfortunately, there is no way to know until you try it out. With every procedure and medication, there are risks involved. Most likely, this would work out for you. Just realize there are complications that can occur that the doctors don't tell you about - mine didn't.
I don't know anyone who has used the copper one. I'm intrigued, but I think I'm going back on the pill. Good luck!