If you really have problems with ownCloud, then please report them at our issue tracker https://github.com/owncloud/core/issues in more detail than »eats files«. Then we can actually fix the problem.
About the delta sync: There’s plans being made and work being done on it. It’s locked because all people get notified on every »+1« comment and that doesn’t help to focus and get actual work done. Besides, do you really believe that USD 1200 will swiftly take care of implementing this feature?