Decent Prototyping Tool - but better options existed for our workflow

We never reached out to Proto.io's support. I never encountered any bugs or issues while using the application, though, so I guess that says something about the quality of the product. We did notice that prototype interaction performance was noticeably slow/laggy when working with a complex prototype. We searched through the app's support forums and crawled the web and saw that other users had similar issues. The response from the company was to simplify the prototype, not ideal.

Proto.io is suitable for what I would call mid-fidelity prototyping. It's good at conveying steps in a workflow with decent facsimiles of interactions/transitions, but not high enough that you can pass it off as the real thing. It's not a bad tool, but we've found that it fills in a kind of useless space in our internal design process. We can get away with presenting the same kind of step-by-step workflow demonstration in InVision. For animation/micro-interaction prototyping, we can use AdobeXD or FramerX if working on a React project (or even non-React if we're designing components instead of trying to go straight to code).