Happy rsync.net client here, thanks for the great service; the ability to use rclone for exactly this purpose, without having to worry about ingress/egress charges, is a huge value-add.
Edit: Will free-of-charge ingress/egress always be a feature of the service? With more customers using rclone for shifting data to/from/between other services, I'd hypothesize that bandwidth use could be creeping up.
Edit 2: A feature I'd love to see would be the ability to setup automated cron-like jobs directly from the admin portal, for e.g. automated rclone backups, eliminating the friction of having to setup another service to periodically run a command on rsync.net. (Tricky to do in a serverless fashion for long-running commands like rclone.) Is this something that might be in the pipeline?