I have a Kyleena IUD! I had it inserted about three years ago and have never had any issues with it. Like any IUD insertion it’s not exactly pleasant, but totally bearable (would recommend taking the day off and relaxing/eating plenty of dessert/watching trash TV. Not necessary but will make the process better!)
With this IUD I almost never get an actual period — maybe one per year — but I do occasionally get other symptoms: cramps, mood swings, break-outs, etc. Nothing extreme though and it doesn’t happen every month.
*One thing I will note: my partner has mentioned a few times that he can feel the strings of the IUD. I’m not sure if he actually can (maybe it’s a phantom feeling because he knows it’s there) but just something to be aware of.