I have had Mirena for about 6 months and I HATE IT! I used to have horrible cramping (stomach-turning camping) and I always could feel myself ovulating. I had a very complicated miscarriage and my OB/GYN pushed me to go on Mirena. She handed me pamphlets on a number of different birth controls (none for the pill because I am "young and will surely forget to take it"). I asked her questions about it at my next visit and she said "I told you to look at the pamphlets!" I asked her if there were risks, what I would feel like after I got it, etc.; she just sort of brushed those negatives off. Kickbacks? I suspect so...
I got it put in, bled... for 4 weeks, not to mention I got horrible cramps that felt like period, ovulation, and a tampon gone wrong all at the same time; I could barely walk. I asked the Doc. later if that was normal. Response "Oh, your body just has to get used to it for 3-6 months..." What?! That would have been nice to know earlier!
Now, I get random periods that last about 2 weeks, random cramping, soreness and uneasy feelings, not to mention some painful and inhibited sex (What is the point in birth control if it never allows you to have sex? Maybe that IS how it works...). As soon as I figure out what my insurance allows, I am getting Mirena removed and going on the pill.
I would NEVER advise ANYONE to get on Mirena.