When comparing Gravizo vs Diagrams.net, the Slant community recommends Diagrams.net for most people. In the question“What is the fastest way to create and edit UML diagrams?” Diagrams.net is ranked 2nd while Gravizo is ranked 10th.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Markdown syntax
Can be used on GitHub using Markdown image tag.
Pro URL
You can use an URL which will be rendered by Gravizo and include it in your website or blog.
Pro Rich functionality for a web-based application
Pro Integrates with multiple cloud storage services
Draw.io offers saving files directly to services such as Google Drive, OneDrive or Dropbox along with saving to to computer.
Pro Real-time collaboration
Pro Great flexibility customizing text labels
Pro Completely free
Pro There is also a Desktop version
Pro Good list of different output formats
Draw.io supports export for PNG, GIF, JPEG, PDF, SVG, HTML, and XML.
Pro Internet Explorer 6-8 and touch device support
Draw.io works with every browser (even IE 6) without plugins.
Cons
Con Online only
No applications for local use in the free version.
Con Import from Visio .vsd is useless
Even simple diagrams get all scattered.
Con Behaves strangely for certain diagram types
For example the snapping function for arrows doesn't work properly for the sequence diagram template.