... is there any benift to the JRiver set up vs the SBT? Is the JRiver redundant or am I missing something?
Not really
I also have an Oppo 103 and a Squeezebox Transporter, and both can stream audio into my receiver. Also my receiver itself is a UPnP renderer so I can stream directly to it too. And indeed my TV is also a UPnP renderer. So in short I have four renderers, all of which can deliver the same bits (bits is bits) into the DAC of my receiver, and so all of them basically sound the same. (Although do be aware of possible sound level differences when comparing different devices).
Personally I still think the Squeezebox User Interface is better than (say) JRiver's Gizmo, or indeed better than any other free market UPnP Control Point. And also (see some of the other threads in this forum) the Squeezebox universe is one of the very few where server, player and control points all fully support gapless playback (indeed they even support adjustable fade over between tracks, which UPnP will never be able to do). So I am still quite a fan of Squeezebox.
However notwithstanding this, I do admittedly have too many boxes, and I am certainly considering letting the Squeezebox Transporter go, and standardising instead on JRiver. Watch this space...