Quip is a great product. I don't use it these days. I like everything about Quip except it's unconventional formatting shortcuts. I have tried various markdown based tools both mobile and web and finally I found Paper is appealing and strikes a balance between visual appeal, share and collaboration. Paper also syncs very small chunks of text (sentence level?) and it reduce conflicts a lot. Though I have used multiple tools for collaboration, the current version of Paper and Google Docs tops the list with my team.