How good is the return for Google's Firefox referral program

I work for a large news-content company in San Francisco. I've been asked to review the potential revenue value of using Google's $1/download for Firefox referral program. I read Google's info about it. I've read that they pay up to $1 based on a sliding scale of where the user is in the world. What I am not able to find are people's real-world responses as to how successful the program is and what percentages of audience utilize the Firefox referral. We have hundreds of thousands of visitors a month so there is a huge potential for this to be a good program for us. If you have had experience with the referral program, would you care to share your experiences?