I had the mirena coil after my first. I suffered badly with pregnancy symptoms (constant) even though I never got pregnant on it. This stopped once I had it removed.
After my second I had the copper coil as I figured hormone contraception was not for me.
It took a while to settle, I had some random spotting and discharge which all checked out as okay.
However once it did settle (took nearly a year) it has been amazing, no issues with it, no pregnancies and I've still got 7 more years before it will need changing.
I think they are great longer term solutions but as they seem to take time for your body to get used to u wouldn't use it short term.
Good luck