OK, just for clarification, from one that has owned both units, and still owns the ODL-276:
The Midiman CO2 is a DFC (digital format convertor) WITH pass-thru capability.
The ODL-276 is a DFC WITHOUT pass-thru capability. It only converts one to the other.
Yes, the CO2 does have the 276 beat in this respect, but since my CO2 gave me drop out within the first 5 minutes of me using it, it was garbage. The Midiman CO2 has been known to have problems related to dropped samples, etc.
In a situation where you need a coax pass-thru, run a coax splitter in front of the ODL, and run all the coax behind you from there. Then run the other coax to your 276 and convert to your optical needs.
Terry