Box now offer a sync client to free accounts. Its similar to dropbox, but a little more resource heavy. I leave it off until I have stuff i want to archive, then dump it in the Box sync folder, fire up the client and let it do it's slow upload. It's time consuming, but more reliable than any cloud to cloud solution, or browser based upload that I've tried (again down to my line quality). I'm now using my Box space to archive photos etc, rather than an external USB drive.