As visible from the screenshots perhaps, grsync was the source of inspiration for me while scratching my own itch.
I think the concept of jobs and tasks in nbRsync differs from grsync, and also how the options are handled. I try to stay close to the CLI notion.
The built in (cron) server and and flexible configuration management are also nice.
That said, I have not used grsync for many years so I dont know how it has evolved.