What are some benefits of using the copper iud?

Safe and effective. The IUD is one of the safest and most cost-effective ways to prevent pregnancy. It is almost as good as getting your tubes tied or a vasectomy in preventing pregnancy.
No hormones! The CopperIUD is one of the BEST forms of birth control available. Non-hormonal (no effect on fertility/acne/headaches/nausea/wt gain/bloating/blood clots) and VERY safe (except if you have Wilson's dz/Copper allergy). Only risk is a heavier period and complications w/ insertion (RARE). Immediately effective to prevent pregnancy, but DOES NOT protect against STIs. OK for women who haven't had kids.