Speaking of security concerns, you might think twice before continuing to use OwnCloud as a part of your password vault solution. It's had critical security bugs in the past, and I'd wager more in the future.

http://www.pcworld.com/article/2845072/ubuntu-owncloud-and-a...

Part of the value of a service like LastPass (not a fan personally, but for argument sake I think ths still holds for this issue) is that someone is (should be) always on duty to monitor the service for suspicious activity and be ready to respond to security issues in the code base. While you're in class or a meeting or a movie or asleep, they can already be locking ish down and implementing patches / fixes.