The concept of the IUD is nice ... worry-free, long-term BC.
I had Mirena for about 5 months then had it removed because I was having screwey cycles (2 weeks on, 2 weeks off, 2 weeks on ...) but that doesn't mean it would happen with you. Otherwise, it was great. Insertion was a bit painful though.
I will say that most ob/gyn's are hesitant to insert an IUD if you have not already had children and/or are married for a couple of reasons ... it's meant to be a long-term (couple years) solutions ... and it's somewhat difficult/painful to have your cervix dialated if you've not borne children previously. I'd had a c-section with DQ, and when I had Mirena inserted, the GYN said I had a cervix like Fort Knox.
... also, while you may not be one of them, you have a lot of young twits out there who confuse birth control with STD-protection.
Now, I also have done (and currently use) the nuvaring and have no side effects, my cycles are normal, and it's almost worry-free (once every 3 weeks isn't bad compared to a pill daily). But that's only until I have my tubes snipped, tied, burned, etc. here in another month or so.