This is really personal, and different for everyone.
I got light periods on my IUD, but it caused pain down into my legs (it was so weird). When I had it removed after only 2 years, I was certain it was the cause of the extra pain. It was.
Im not on anything now, we use condoms, the wierd leg pain stopped as soon as I removed the IUD.
While it can help some folks, like most things, there's never a one size fits all answer.