I'm syncing a collection. Granted, it's over 10,000 photos ...But, in half an hour it hasn't yet synced a single photo!
Here's a screenshot:
Dropbox - Screenshot 2015-01-18 16.10.00.png
I have only synchronized a couple of small collections. Fewer than 20 images in each. But the collections were synchronized in a matter of just a few seconds. Either you aren't connected or perhaps you are trying to synchronize too much at once.
Retrieving data ...