I decided against paraguard because I'd heard it makes cramps worse and periods heavier. Since I was already dealing with nightmarish periods, I was looking for a way to calm things down a bit. Mirena did that. It's not perfect-- there's annoying random spotting (still, after two years) and my PMS is unchanged or maybe a tad worse. But my periods are much more tolerable now, so on balance, it's pretty good.