One of the most important thing while in the early stage is the flow chart. With Moqups, I can do flow chart and wireframe, sitemap all in one project which is awesome for managing.
Loading is a bit time costing also the sharing and deletes page user flow is a bit strange to understand. I often accidentally delete a page by the misleading UI. also the template components should be managed in one source just as sketch symbols. Now if something changed after I created a template component, I'll have to add new and delete the previous one and go to every page to attach which is really not helping to create components.
It's good for team collaborating if members want to discuss flow, function and do quick wireframe. And one of the best things I enjoy is sharing.
I use mockups to communicate and clarify the needs of the client. The best thing of Moqups is to share with one click just like google doc, which can manage the access permission within. Also can see the editing history that is important when collaborating.