What are some alternatives?
Sitefinity - Sitefinity is a Web Content Management System that leverages the .NET 4.
M-Files - M-Files is an enterprise information management system that helps users with organizing and managing documents.
Drupal - Drupal - the leading open-source CMS for ambitious digital experiences that reach your audience across multiple channels. Because we all have different needs, Drupal allows you to create a unique space in a world of cookie-cutter solutions.
Laserfiche - Laserfiche offers powerful document management software solutions that are easy to implement and easy to use.
Joomla - Joomla! is the mobile-ready and user-friendly way to build your website. Choose from thousands of features and designs. Joomla! is free and open source.
Box - Box offers secure content management and collaboration for individuals, teams and businesses, enabling secure file sharing and access to your files online.