'old timer' yuri players are experimenting with CNCNet right now. And the reviews i've heard/read all seem favorable. This is having a direct effect on XWIS RA2 activity, since many of the mainstays here are pro Yuri players whom were forced to make the switch to RA2 due to activity. I would say that GR is experiencing similar issues, although this is only based on perception, since listed games during the times i normally play seem to be almost 50% less.
If/when CNC net gets RA2 up and running will truly be the test. RA2 seems to have always been the rock that helps drive activity.
Like Brekurass says, there really isn't much choice, if you are looking to play right now. When i check the lobby and there's 8 players and 1 game open on XWIS, i look at GR; Like i mentioned, even GR seems to be showing a decrease, so if CNCnet is a 3rd option.
I do feel like every option is suffering with the watering down of available servers to play. I don't know if a 'winner' can be crowned.