The problem for home users comes in little gotchas like dynamic IP addresses. So you give your Pi a static address and set up port forwarding and get some DNS help from noip.com or similar. At which point, enter the owncloud config file stage left. The help file for this is plain inadequate and arguably misleading. Certainly the default set up is no good for a home user - unless you only ever want to access your data from your home LAN. The interweb gives 100 different answers on how to set up the config file and if none of them work you're on your own as to whether it's port forwarding of NginX or Apache or Owncloud or...

So I haven't fixed that yet and it's only one of the problems I hit.

Got it up and running. It's free and so far it seems to work. It doesn't have the slick functionality of offerings such as dropbox and Google drive etc. but it actually has enough functionality to work and I'm sure that much of the lag and patchy connectivity etc. are down to my network which isn't exactly bullet proof enterprise standard. If you're in urgent need of a large amount of disk space that you can get at from multiple devices and across the internet, this might be worth considering.

The project has just had an acrimonious split as open source projects often do, with the founder developer and some of his fellow developers leaving to start Nextcloud (which is pretty well identical to ownCloud at the moment). Nextcloud seems to be run on a rather more traditional open source basis. No idea whether one or both will survive.