I had the mirena twice, never any issues, never had a period, I loved it. After getting it removed it took 9 months to get pregnant. You hear good and bad about all birth control methods though.
I had the paraguard iud for 2 years. That's the copper, hormone free one that last 10 years. I loved it, although my partner could feel the strings during sex, and if I was on top, it would hurt really bad.. Then one month, my period never came... And with this one, you keep your normal cycle each month.. My period didn't come for 3 months and I finally had it removed because they couldn't figure out why it stopped. I wasn't pregnant, and if you do get pregnant with it, your very likely going to miscarry. Oh, and when I did have my period, I bled extremely heavy, and the cramps were awful. I plan to breast feed so I'm going to take the birth control pill that you can take while breast feeding
I had Mirena for 4 years no problems until the last 3 months had it removed and concieved my daughter within 4 months and didn't have a period for 3 years. I loved it.