A study jointly commissioned by WP Engine and Manifesto surveyed over 300 enterprise-level IT and marketing decision makers in the US. and UK. A few key points stood out: Adobe Experience Manager won the popularity contest, but it was followed closely by WordPress, which is highly favored as a “secondary CMS.”
Keep in mind this is a sampled survey but it’s an interesting snapshot of the enterprise world, where WordPress has been steadily gaining serious attention over the last few years.