I would weigh in on Resilio Sync too. I have been using it for years (free version) and was really looking forward to Steve’s promised review of their security and privacy brief here.
Sure it’s proprietary and they don’t give us all the technical details, but the brief reads pretty clearly and as long as they’re not outright lying to us, it seems securely designed. Data transfer is peer to peer (unless a relay server is needed because of NAT). Only the clients have the keys and nothing is stored on their servers. Transfers are really fast and I believe it is smart about differential syncing. Since it’s peer to peer, the only storage limit is the size of your hard drive. You can sync arbitrary folders too, not just the sync folder.
Of course we have to trust that they’re doing what they’re saying, but since getting caught doing funny business would be the end of their business, I have no reason to doubt their intentions. Open source would be preferred, but I’ll still take it.
The UI is not perfect, but gets the job done. Leo will be happy to know that it runs on Linux and Mac too. I have a Raspberry Pi with a big USB hard drive at my parents’ house for off-site backup. It uses a neat “Encrypted folder” feature where the remote data remains encrypted at rest (so my parents can’t see it). In return, I give them an encrypted folder on my machine so we both get off-site backup (without exposing our data to each other).
Anyway, sorry for the sales pitch, but I just don’t feel like it got a fair representation on the podcast. I’ll try Syncthing when I get a chance, but this is easier for now.