OpenX was one of the most popular alternatives to be used as an Adserver. However, recently we experimenting really huge problems using OpenX which was extremely slow compared with Doubleclick Google AdPlanner that made us switch from OpenX to AdPlanner. Instead, we could deliver ads reliable using Google platform , which use maybe one of the biggest and more robust platform in the world.
If you are looking for ad server software, then you should know that there are many alternatives to use, but clearly Google Adplanner that was bought to Doubleclick by Google is one of the best choices and easier than OpenX.
Online ad management can be used with other tools, however, for example if you run a WordPress blog then you can install WordPress plugins to use Adsense or other advertisers.
Another big advantage of using AdPlanner is that it is a free ad server, and you can manage different websites or a network of sites or blog. The ad serving technology behind Google Ad Planner is a top notch technology with incredible performance that makes the ad management easier.
When comparing Google ad manager vs OpenX you should also know than there are big technological differences between services. While the first one is a Google product using Google’s infrastructure, the other runs their own servers.
Another great alternative ad server is Ad Serving Solutions http://www.adservingsolutions.com We use their ad server software and rave about it.