I love my IUD, to me it hurt as much as a pap smear both times. I now have to Paragaurd IUD (it has no hormones and can be used for up to 10 years) because the Mirena (although I loved it) does have hormones and I wasn't able to concieve right after it was removed. It took a year and a half to get pregnant. I didn't have a period at all after three months of getting the Mirena. The Paragaurd IUD works for 10 years....I would strongly suggest either, it's hassle free.
Since I got Mirena inserted, I haven't had a real period yet, but I bleed here and there and have regular cramping. It's a real birth control device, because I never have sex because I'm always bleeding . . lol. I don't care though, my daughter is only 5 months old, so I'd rather bleed a little bit than get pregnant . . . DEFINITELY NOT ready for another one.
I love my Mirena, it is worry free, you can't feel it, you don't have to remember anything either. There is the chance of bleeding and or spotting for the first couple months after insertion though. I lucked out and only bled for three days after getting mine, and I had my period as normal the following month.