Earlier quoted context omitted.
I use owncloud (and then dropbox inside it so some files are double backed up). I find it to be just fine. Have you had any problems with it?
Yes, last time I tried it, had a variety of conflict issues plus the client had some problems, performance and otherwise. If you're just using it as a backup solution (does it even keep file history?) from a single machine + mobile/web access, it may well work acceptably.
Personally, I use KDE's file manager (Dolphin). Plus a curl-cased Bash script for when I need to upload an arbitrary file from one of my home computers via my phone (SSH from phone to computer, sometimes over sat link, run "~/bin/upload.sh /some/file").
I manage my own ownCloud servers (one personal, one company), but hosted options are available.
And yes, it does keep file history (optional, enabled by default), as well as encrypted storage (optional, disabled by default).
Neither the client, nor the server even, require any administrative access.