The conversion optimizer feature in Google AdWords is now out of beta.  To be eligible for conversion optimizer, the campaign must produce at least 100 conversions in a 30 day period.  That number was reduced from the 200 conversions necessary when it was in beta.  Google explains their conversion optimizer as, a free AdWords feature for managing cost-per-acquisition (CPA) bids. This feature enables you to set maximum CPA bids for your ad groups, helping you save time and make the most of your advertising costs.

I was a little discouraged by the campaign performance when I tested this feature in beta, however, now that testing is done, I will happily test out conversion optimizer again and report back with my findings.

FYI - You will not be eligible for conversion optimizer if you are not tracking conversions.  Click here for more information regarding conversion tracking.