We've done both twice. Most recently CG in March. It seems two of the words most used for the dining experience are "elegant" and "intimate." Ironically, for both restaurants. So for what it is worth...
I would rate CG as the more elegant. From the private elevator ride, to the overwhelming first look at the what seems like never-ending wine cases, it was an unreal experience for a simple couple from the Midwest. On our first trip to CG for our 30th wedding anniversary we had a perfect inside view. Just turned our chairs a little to take it all in. This past March, we were seated farther back, so we went outside. A little cool and breezy but still a fantastic view. Personally, I prefer the fireworks view at CG because I like to take in the whole park. Even the bus stops and train station add to the panorama of it all.
At least for our trips, Narcoossees was the more intimate. We could have been the only two in the restaurant. While we did not have a problem with the outside guests blocking our view, and we had window seats both times, the fireworks just didn't seem to have the same flair as at the CG. And our last time at CG it did seem quite loud. I do not remember that from our first trip.
We have had great food and service at both restaurants. But I will say this; the BBQ shrimp and grits at Narcoossees is not just the best appetizer I have had, it might be the best thing I have ever had to eat.
OK, now I need to plan another trip and book them both again!