I’ve heard a lot about ownCloud being poor in security and stability (as in: it struggles with large files) - are these still true?
I was running owncloud up until a few months ago (on Debian-ish systems). The “official” package repositories had their GPG key expire, and I think it took months to update it. The Ubuntu/Canonical package stopped getting updated too, if I recall correctly. But, I suspect these issues wouldn’t be as much of a problem with the way the ports system works on the BSDs (and of course, you can always do a source installation on linux too).
As for other security issues, I’d say that owncloud suffers from similar security issues as other well known PHP web apps (thinking Wordpress, Drupal, etc). But, being open source, we can hope those issues are caught quickly and updated.
I don’t remember large file syncing to be too problematic. The client got a little CPU hungry every once in a while, but nothing terrible.
In any case, I was only using the owncloud syncing, and wasn’t happy with the packaging issues, so I switched to Syncthing, and have been pretty happy with it. Clients and protocol are open, written in Go, overall pretty neat :)
Ah, and to add, the only real thing I miss from owncloud was that they had mobile apps for iOS and Android, Syncthing is only on Android right now (but I think Go is available soon in iOS, so maybe it’ll show up there soon!).