Strictly speaking, the thicker one (23 AWG) would have less resistance to DC current. However, DC resistance is not the only characteristics that you should look for. Also there are NEXT, FEXT, Return loss and actually plenty of others.
I would suggest that you request electrical performance specs from the vendors and check all the data they supply. This is the only way to tell which one is better.
Besides, ther is one side effect for 23AWG copper wire: once you terminate it with, say jack, you cannot use this jack for anything else but 23 AWG. And most of the cables available on the market is 24 AWG.
Hope this helps.
Dmitri Abaimov, RCDD