When comparing Diagrams.net vs MockFlow, the Slant community recommends Diagrams.net for most people. In the question“What are the best mockup and wireframing tools for websites?” Diagrams.net is ranked 6th while MockFlow is ranked 29th.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
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.
Pro Export to PNG, PDF, HTML
Export to PNG, PDF and HTML formats.
Pro Easy to learn
Easy to pick-up. In few minutes you can sketch your first pages.
Pro Online software
You can use it online. No download, no install, no mess.
Pro Free basic account
The free basic account give you a lot of features, all for free, forever.
Pro HTML5 rendering
Use many Bootstrap components and get the HTML5 view quickly. Sketch, see, repeat.
Cons
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.
Con Need a Flash plugin
Flash is a technology of the past. Unfortunately, they use it. "MockFlow requires Flash Player 10 or above."