Differential Sync might be the only feature that makes Dropbox so much better than OneDrive. Differential Sync lets you sync only that specific part of a file, which has been modified. Consequently, this reduces the bandwidth requirement for sync and reduces the required time too.
Microsoft’s OneDrive roadmap at Ignite in October 2016 didn’t have any mentions of Differential sync, but recent roadmap has portrays quite a different story. As found out by Mary Jo Foley from ZDNet, Differential sync is coming, that too in the next quarter Q2 2017. This feature has been much requested by both public and business users in the past.
Apart from differential sync, OneDrive will recieve auto tagging of photos, OCR, whiteboard cleanup, @mentions and comments and much more cool features in Q2 update.