Dia diagram is the smallest and simplest free tool for drawing variety of shapes which makes presentation of flowchart easy. While comparing with other software's it provide larnge number of shapes thus making the preparation of slides and other flowchart easier. This software can be used for many proposes

Its interface and functions are very friendly and easy to use. The program includes printing several pages, exporting to many formats (EPS, SVG, CGM and PNG), and gives us the option to use custom created forms. The program is very useful for the elaboration of UML diagrams, network maps and flow diagrams. Diagram Editor Day is easy to learn and very efficient to use and observe the quality of the results, plus it is flexible enough to allow you to create highly customized diagrams.

The simplicity of the software is the most likely thing for me. Is so easy to use, easy to configure and easy to install. You can deploy every documentation or project using this software for the diagrams and draws of your network. Another important thing is that the free version has almost he same features of the pay version, so you can pay only if you need to. Has variety of features and symbols and options by default and if you need something additional you can download it quickly. Also, you can export your draws in almost all the extensions and formats.