M.R.
Ora~ First congratulations on your upcoming baby. I have a few friends on IUD's (both copper and hormonal) I have heard some very positive feed back. As with any form of medication there are positives and negatives. I am also in the research mode for finding a new type of birthcontrol and have found a lot on the web. Minera has a website www.mirena-us.com, it has some helpful information, but remember that it will put the positive spin on their drug. I have had a lot of success on the Berkely Parents network. Here is a link to the IUD question page. http://parents.berkeley.edu/advice/parents/iud.html
Good luck!