I have done promotion for the company I work for using Overture, Findwhat, Kanoodle, Banner advertisements on more than 20 different sites, E-Mail Newsletters etc. We have found that google AdWords has the best return on investment of any advertising we have done. We now spend more than $1000/month on AdWords and will probably expand more. The 2nd best performing advertising we do is a CPC business.com listing, but AdWords return is almost double that of business.com.
One note, we have done extensive testing of the content network to promote several of our businesses. Returns on content network traffic are much less than search and as such we have discontinued all promotion on the content network.
Yes, I have used Google Adword to run a campaign for PapaChina and it gives an excellent traffic. A Google Adword is an advertising system where the advertiser bid on their keywords to get the traffic and see their website on a top-level in the Google search result page.