Everybody knows about Webform so why would we want another survey system in Drupal? Entityforms takes a very different approach by using an entity and standard fields approach to forms. Entityform submissions are field-able entities.
This has many advantages including being able to use virtually any field module in Drupal. Now you can easily gather geographic information, reference site content and include media references in your surveys and other forms. It also allows for simple integration with popular entity-aware modules such as Views, to handle submission lists and Rules, to handle notifications and form access.