While I don't own either, (my 6.5 is the Swede), there's no way to tell which one will "win out" in the commercial market. Odds are the one best suited to the AR platform will have an edge in sales.
If I were going to get one, I would choose the 2.60 Rem. Simply because I have a number of rifles using the .308 Win as the parent case, already.
This is not quite the same situation as the .222Rem Mag vs. .223.
The Army is not involved! Nor the other beancounters in the federal bureaucracy. They set a standard that was just beyond what could be reached with the .222 Rem. The .222 Rem mag could meet it. But the .222 Rem Mag was just a bit too long to work in the AR rifle. End result, .223 Rem (5.56mm).
(and, just FYI, the standard required back then has been proven to be essentially meaningless in the real world. Todays heavier bullet loads and short barrel carbines don't meet it, either.)