As far as the amazon item is concerned - all data provided seems to be the same as the ebay one posted above. They look the same, that of specs that is given match - beyond that I wouldn't really know. I only have the one I bought from DX. You could always send them a mail etc, ask if it is a C-media CM106 controller inside. If in any case you get it and it is the C-media CM106 one, and you should happen to install on windows - DO install the drivers I linked to, do NOT stick with the windows drivers, they lack most capabilites, including the configuration tools. For Ubuntu, all should be there I guess - but might need some configuration.
As far as ubuntu go, I know there were some issues with this model 3 years ago - I would highly suspect this has been fixed by now - as the bugs were confirmed and work was done.
Just FIY - there
are optical -> coaxial , and coaxial -> optical SPDIF adapters available - can be had cheap on ebay etc - a bit more expensive on Amazon. But bare in mind: These are active adapters, thus require power from wall socket (wall wart usually included), and they are
one-way adapters! This means, if your audio source
output is optical and the soundbar/av reciever etc,
input is coaxial - you need an
optical -> coaxial adapter (coverter). Input -> Output.
Optical -> Coaxial
Coaxial -> Optical