So I have my phone pics synced to my NAS and PC, my blog's markdown files between server and my computers, another dir for some music etc. There is also option for simple versioning in case you need to dig out the old files but it's not integrated with OS as it is "just a directory".
Disadvantages is that you need at least one other device running to sync as it is P2P (with some community-ran server to forward if you're NATed out of sight) but other than that, literally zero problems.