I tried and failed to make Unison use its fast comparison method (timestamp and size) but FreeFileSync works great for that and I can recommend it especially for interactive syncing of folders. <a href="http:&#x2F;&#x2F;www.freefilesync.org&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.freefilesync.org&#x2F;</a>