Alternatives to OwnCloud:
(1) Bittorrent Sync: Its P2P idea is very attractive, but currently it is not reliable even with its basic purpose: sync and update with the right version of a file. Sometimes, it accidentally delete files; Sometimes, it overwrites new files with way old files. This happened to me just twos before I was going to submit my critical project deadline. Many other users also reported similar data lose. I will never use it before they have reliably implemented conflict management.
Secondly, Bittorrent Sync is closed source. Its company is so money hungry that advertizes and charges for such beta software without conflict management, not caring about the damage it could bring to its users. As closed source, it is not sure how secure their btsync is. In their forum, they lock discussion on btsync’s alternatives and questions on its security. Such attitude drives me away.
Third, btsync runs in background without telling the user with a task bar icon. It is very sneaky. If some one install on your computer, then it becomes a backdoor. Your data is sent somewhere without telling you. Damn! Keep far away from this software and this irresponsible company until they prove they are trustful.
Do not use Bittorrent Sync until they have implemented conflict management, if you really care about your data safety.
(2) AeroFS: AeroFS runs on virtual machines. This is both good and bad. I eventually gave it up because on a Linux host machine with wireless connection, its guest machine cannot have a unique MAC, but must use the same as the host machine. It may introduce many trouble in your LAN. If you use a Windows as a host, it shall be fine. By the way, their virtual machine appliance is really resource hungry. In comparison, OwnCloud takes much less resource.