Carl,
If you already have the 706, then I would say that there is no need to
buy a new rig. Each has its advantages and disadvantages: The 706 needs
to have you "build" the cable for the connection between RRC and radio/RRC
control panel, the TS-480 uses a simple 3-line telephone cord. You need a
separate serial cable on COM2 for CAT for the TS-480, the 706 uses COM0.
I am sure there are several more, none of which should create a reason to
switch from the 706 if you are satisfied. And note that I am a TS-480 user.
73,
Mitch DJ0QN / K7DX