When comparing Moqups vs Diagrams.net, the Slant community recommends Moqups for most people. In the question“What are the best mockup and wireframing tools for websites?” Moqups is ranked 1st while Diagrams.net is ranked 6th. The most important reason people chose Moqups is:
Moqups is built in HTML5 and standard Javascript, so it doesn't require any plugins to use. The application is very fast to use.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Fast and doesn't require any plugins
Moqups is built in HTML5 and standard Javascript, so it doesn't require any plugins to use. The application is very fast to use.
Pro Supports 960gs
As well as a standard snap-to-grid, Moqups supports the 960 gridsystem.
Pro Free tier
The Free Plan offers 2 active projects with at most 300 stencils each and 5 MB of storage. This plan does not include: Master Pages, Real Time Collaboration, Privacy Settings, Unlimited Revisions, Unlimited Project Archiving and Teams.
Pro Clean design and very intuitive
Pro Keyboard shortcuts
Moqups has an extensive list of keyboard shortcuts. Simply type some A-Z letters to search for components. F1 for an overlay help screen.
Pro Modern Material elements
Pro Free upgrades for nonprofit/education
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 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.