I came across this recently. It is a very good Dropbox alternative, in some respects it is even better.
For example you can sync any folder on your computer rather than just have one specific folder like in Dropbox. Also specific folders on various machines can be linked together and synced so their content is identical across all computers.
Also you get 5gb free storage rather than 2gb with Dropbox.
Right now I am using both Dropbox and SugarSync, there is no reason not
If you want to check it out use my referral for extra 500mb (only 250mb with Dropbox).
https://www.sugarsync.com/referral?rf=c890777jaiegk