Wanted to try it because of all the great reviews.
I tried but did not see any SEO improvements. Impressions moved laterally only. In the fourth week, I saw a dip of 80% in my impressions. I have just removed the code from my site, so I hope my impressions come back up. I will admit, it is impossible to determine what exactly caused a drop in impressions so dramatic, but then again, I can say my SEO did not get any better.
Contacted tech support to see if they knew what was happening, and I was told it was due to a Google update. I asked additional questions and never heard back.