I've had it in for almost 2 years and for the most part I like it. I can't take pills because I forget and I breastfeed, so it was really the only option.
I've done a lot of talking recently though to others and hearing about the weight struggles and mood swings, I am beginning to wonder if it's related to my Mirena, cause I've got those issues too. I'm having a terrible time losing weight even with diet and exercise, seem to go through a roller coaster of mild depression every month and I do definitely get PMS. My period has gone to a spotty, sporadic every 45-60 days kind of thing, but I get bloated, crampy, headaches, etc.
My husband has felt it at times too, which he hates. All in all, it is tremendously convenient and I LOVE that, but I grow more concerned about the side effects the longer it stays in.