I am coming from syncthing after facing a lot of out of sync problems, and wanted a fire and forget solution for my setup. I have other "problems" but this one is more critical right now.
I have a PC, Laptop, and 3 android that I sync with.
The PC is the only master (read only)
In the other devices: I turn off the selective sync (so files are always in sync when connected), and I also turned on "overwrite changed files"
I saw some out of sync items yesterday, so I deleted them on the other devices and let the PC overwrites them with the fresh updated files.
Today: I see some (new) out of sync items, and they all have a "%" symbol in the file name. I deleted those files and let it sync. I was able to sync, at least sync tells me it's 100% done. I went to the android folder and checked, the file name is now different. The % is now display as �, (unicode: black diamond with a question mark inside), the extension . dot is now replace with the underscore _ , and at the end I see the (1), (2), (3), for the other copies (but I turn off the archive function) When I browse with the sync directory, it displays fine, but when I use my file manager program or the music player, it will not open it.