This took me a good half a day of endless testing - here's my findings: these days there's some beautiful automatic real-time FTP<->PC dropbox-like sync apps, which really are a dream to use. Well, almost. Only ONE truly can be considered (at this point in time): and it's GoodSync. It's consistently reliable and fast and smooth (enough). Other solutions have either deal-breaking bugs or glitches, or feature lackings.
There is a GREAT one called Fling - it's PERFECT - in EVERY WAY!!!! - except, oh, hmm, it doesn't update the ftp server when you DELETE files. it can only add, or modify....it's really an uploading tool, that one. unless someone asks them to add the lacking feature to the app.
And then FTPBox is the other mentionable, but after 10 minutes of trying it out, it's a no-go: it was jittery in its constant 'file x was uploaded' notifications when those certain files didn't even need to be re-synced, and while even updating a file from the local pc, it seemed to then override it with the penultimate version from on the server!!
So it's GoodSync, people, tried and tested.
Eventually, the golden daddy of them all looks to be SyncAny, but it's not out yet. Spose it's worth waiting for that one!