To get even more speed, you might want to checkout running rsync in parallel, for instance with http://moo.nac.uci.edu/~hjm/parsync/ . I found this to work best to exploit fast uplinks (such as 10GB/sec) and also exploits hardware parallelism if the sender and or reciever has uses distributed file system.

Adding GUIs to command line utilities is often pointless. It reminds me of this: https://i.imgur.com/sVYvCHX.png

how did you measure speed?