It sounds like you've had some bad experiences and I don't know which projects address those specific issues, but personally I've had good luck with Unison. So

It sounds like you've had some bad experiences and I don't know which projects address those specific issues, but personally I've had good luck with Unison. Somebody else pointed me toward lsyncd which seems to take an interesting (inotify-based) approach which might meet your "in the background" requirement better, but I don't have any experience with it. I know there are lots of others, with varying levels of maturity and "intelligence" regarding things like conflicts and moves/renames, but it's such a crowded field that I don't claim to be an expert. My attitude is generally is that if you start with something that can be used live then it's trivial to use it for syncing instead, whereas something that's originally designed for syncing might never go the other way. Right now I just rsync to the remote directory, then from it, whenever I feel like. I could automate the process, or replace rsync with something more sophisticated, but my focus is mostly on the remote-infrastructure side because that's where I see a dearth of suitable alternatives.