There are several tools you could use for the synchronisation of folders – but in this case I was looking for something that would work with FTP folders and potential as a means of syncronising client backups. I came up with a shortlist of 4 which I will detail here
1) Bestsync Version 7 from here
2) Goodsync V9 from here
3) Allway Sync from here
and finally
4) Syncback Pro from here
Each of them has its merits – most have free versions without all the functionailty. Take a look at the alternatives and see if any of these suit your purposes. I will be reviewing these 4 options in the future to see which is suitable for a project I am investigating for clients.