Proto.io can be more complicated than some of those tools because it gives us a lot of features in the same product. Some of those tools are better for wireframing. Still, for prototyping, my choice is Proto.io because its prototyping workflow, even if it can be a little …
In the end, we decided not to continue using Proto.io and instead use tools we were already using.
For just presenting workflows to stakeholders, InVision worked almost as well (not as robust in interactions, but when you want to focus on the steps, that's better anyway).
Proto.io is definitely the premier mockup and wireframe application. Lucidchart shares some of the capability but can be a bit clunky. Proto.io is interactive and smooth and helps you to see exactly how your UI will look and behave before the development stage. Additionally, …
Proto.io is web-based for one, which is a plus - Adobe XD is a desktop application. Adobe XD has some great features, especially for a free product, but from what I experienced Proto.io had way more tools and customization for creating interactive prototypes. Adobe XD is good …
Proto.io is an excellent product for small to medium teams that wants to have a prototyping or wireframing tool that is easy to use, can be used in collaboration with others and will deliver superior results with less efforts than similar options in the market. I think it is not so suited for teams that don't have more complex prototyping needs. In this case, other tools that are even simpler could be a better fit.
Proto.io is web-based for one, which is a plus - Adobe XD is a desktop application. Adobe XD has some great features, especially for a free product, but from what I experienced Proto.io had way more tools and customization for creating interactive prototypes. Adobe XD is good for building prototypes that go from screen to screen, but Proto.io allows you to get much more detailed with that (every element on the screen can have an interaction).