Another point to consider when choosing a prototyping tool is how well it fits your design process and other tools you regularly use. Prototyping is part of a much broader process that includes researching users, testing, gathering metrics, communicating the idea to stakeholders, and sharing designs with developers for final implementation.
You probably won’t find one tool that does everything (more on this later), but prototyping tools should at least help you move through the process smoothly, especially when you are expected to iterate under tight deadlines.
For example, if you are designing in Photoshop, Illustrator or Sketch, it would be great if your prototyping software could directly use the files produced by these apps without requiring you to export assets separately and then build everything from scratch to create the interactions.
Set up, record, observe, and analyze usability studies, focus groups, field research, and product testing. Watch the study or interaction...