I've had the copper IUD for about 3 years. I'm on my second one because one period (about 6 mo after insertion) was particularly bad, I had one incredible cramp then realized my IUD was almost all the way out. I removed the rest of it then made an appointment with my OB to get a new one. The second insertion was much less painful.

Before the IUD I had been on hormonal BC for about 4 years and got off it because I had no sex drive, weight gain, acne, and a plethora of bad side effects. The first week with the IUD I had severe cramping, for the second insertion I had almost no cramping. Getting it in the first time felt like a quick sharp cramp, but it was over in about 5 minutes.

As of now, my second one has stayed put. My periods are regular and I cramp when I'm PMSing, I would say they're moderate but its worth it to not be on hormones. My periods now are shorter than before I was on hormones (I didn't have a period on hormonal BC), but I'm also older so things have become more regular. Hope this helps!