It's free, anybody can install it without any subscription. Also available for mobile phones.<br><br>It can downgrade or upgrade the file version easily.<br><br>Best for reviewing a file (read only) when multiple users are working on the file at the same time.<br><br>User interface is good Review collected by and hosted on G2.com.

The issue that I faced with this is opening/handling large size files. Sometimes it gets stuck and closes automatically.<br><br>Navigating through 3D drawings or views can be slow at times. Review collected by and hosted on G2.com.