copper IUD

I have read a lot of negative stuff about the Mirena IUD and I was wondering if anyone had any experiance with the copper IUD (non-hormonal). I am looking for a fairly "secure" reversible form of birth control, that gives you the option of being spontanious and is non-hormonal. Any input is greatly appreciated.
Oh, by the way: I currently have a 10-week old boy and I am planning to breastfeed for a while. Right now I am taking the NOR-Q pill (because I just cant get pregnant again right away), but I am not dealing well with the hormones and I really need something else.
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