I got the Merena IUD. Researched it for weeks and decided it was the best way to give us time in making a final decision on whether or not we want another baby. After getting it inserted, I pretty much had bleeding for 3 1/2-4 months straight. It was horrible. I had cramping, lost all sexual contact with my husband because things felt uncomfortable down there, and add the bleeding onto it, and it was just not great. Everyone tells me that once you get past the initial 3-4 months of bleeding, it lightens and you barely see your period, but the first 4 months were so unbearable to me, I had to get it removed. It almost felt like it was fighting my body to do something my body naturally wanted to do. Also, since then, my periods have never been the same. It was a lot of out-of-pocket expense for 4 months of birth control.
This is only my experience. I have heard of many that have an IUD and love it. It just wasn't for me. We now watch my cycle to avoid intercourse when I'm ovulating and use condoms.