Since no one is complaining: I find Syncthing too complicated to set up. You must create a folder, then get a number for a computer (which you end up writing in a pastepad or something like that because the two computers don't communicate), then go to the other computer and place the number in, then do the same for the second computer to the first. Repeat it for 5 or 6 machines. If any machine is switched what do you…
This is the price you have to pay for a (secure) decentralised system, but syncthing tries to help where it can. E.g. you can set a syncthing instance as an 'introducer', so you only have to establish a connection to this device to get offered connections to all others devices. You still need to authorise these introductions on the devices, but you do not need to type in the crypto verification strings.
In general, Resilio Sync's 'key per folder' model seems to work better. I can give a key to other people and they can join the swarm without extra work on either sides. Also, it has a logical extension to encrypted-only peers: they get a derived key that can be used to sync in the swarm, but cannot decrypt the data.
If there was a stable open source program using Resilio Sync's sharing model, I would switch in a heartbeat. (There is Librevault, but it still seems to be mostly in development.)