Honestly, I hated it. Cost wise it wasn't overly expensive and if you have a health care card (I don't) you will get it cheaper because I got a script for it and then took it back to my Dr to have it injected. Not sure if you can use it as birth control when you are BF though, so that's something to look into.

I had a lot of issues with it - bleeding for a week or more every few weeks, sub zero libido, couldn't lose weight and just a general feeling of crappiness. Plus I only ever had the one injection and it took months for my cycle to go back to normal after the 3mths effectiveness was up, so I vowed never to have it again.

ETA - the only 'pro' was that I didn't have to remember to take a pill each night. Other than that it was all con