I liked that it was easy to use, with simple commands like "cw" (send character), as well as being able to send files over USB or Ethernet connections in any OS from Windows 7 up - even MacOS! It's also very configurable so you can set your modem speed/bandwidth etc if needed. The downside for me has been some bugs which have slowed down my workflow at times; especially when sending large amounts data via telnet connection using command line interface.
If anyone wants an extremely reliable tool