I have the Mirena. have had it for almost 2.5 yrs. I have not had a period in 8 mos (I also quit having them on the pill and patch-estrogen issues), but U/S says the lining of the uterus is thin, so no concerns there. The progesterone is more localized than taking the mini pill or depo. I have not had any significant weight gain (I stay at or around 130's)or mood issues (again, pesky estrogens) other than normal

As for ovulations, I knew prior to my recent dx that I was oligoovulatory, so I never knew when I ovulated anyway. I had very light periods for the first year, and even those were hit or miss. I would say go for it as long as having no period after a time doesn't get on your nerves.