So at our store’s we use dropbox for most of our files, however there are some files which have proven to be difficult to put into dropbox folders. For instance sometimes we need to share 60-100GB of files between the computers, and if you push them through dropbox it will take over a day at times to transfer the files.
So in my research I found syncthing, which allows you to sync folders between multiple computers and seems to be much faster than dropbox. It does take a little extra effort to set up but once it is it does seem to sync fairly quickly.
You can find out more information on syncthing by going to Syncthing