i went with the paragard when it came time to choose. i chose it specially because of the reasons that you mentioned. hormonal birth control and i don't get along. i'm always the one who gains a bunch of weight, or whose cycle completely stops, or you name it and i've had it.
you may want to think long and hard about the mirena if you don't want the side effects because as you know you can't pick and choose which ones you end up with.