We've done all three numerous times (pretty much every trip), and if I had to choose only one, it would probably be in this order:
1) CG
2) Narcoossees
3) Citricos
We really love Narcoosees, so it's almost a tie with CG. Citricos has failed to really really wow us with the food, (though it IS good) and we've had snotty service there (which we have never had at the other 2), but we keep going back because it's got nice atmosphere (comfy chairs!) and it's relatively quiet.
CG has a more "unique" feel to it for some reason, while Narcoossees seems like a lot of other similar restaurants. (though we always have great service there, especially the wine service) We like that Narcoossees has a somewhat more casual vibe than the others too.