The author, who works in marketing agencies for over ten years, shares their experience with various flowchart software and diagram tools. They tested 12 apps, including Lucidchart, Microsoft Visio, Textografo, SmartDraw, Zapier Canvas, Whimsical, FlowMapp, Venngage, Creately, FigJam, and Mural, to determine the best options for different types of users. The author highlights features such as ease of use, templates, team collaboration, AI and advanced features, value for price, and two-way data synchronization as key considerations. They conclude that while there is no perfect app, these 12 apps are among the best diagram and flowchart software options for most people, and recommend testing them to find the one that meets individual needs.