Ok, here are some of my observations of the trifecta of animation industries:
Cartoon Network is the idealistic network of this generation. What makes them superior to other competitors is their willingness to experiment with entertainment, but even more advantageous than that is the creative freedom they give to their content creators. After the drought of decent shows and many forgettable or just plain bad ones from the turn of the century (which arguably had some good ones far and in between) CN became a pace setter. The popularity of "Adventure Time" and "Regular Show" are marked by many as the starting point for the current generation of animation. The success of these shows opened up a pathway for more quality cartoons such as "Steven Universe", "Clarence", "The Amazing World of Gumball", "Over the Garden Wall" and others.
As a company, Disney has been around since the golden age of animation. It sits in the middle ground. Over the years the Disney Channel has shifted its focus from actual animation to cheesy "whacky fun" sitcoms. But they apparently seem to be taking a lesson from CN and making some admirable shows such as the cult classic "Gravity Falls." Other praise worthy Disney shows include "Wonder over Yonder" and the upcoming "Star vs the Forces of Evil."
Also piggy backing onto the Disney channel is Disney XD. This network was conceived to be the edgy "for guys" incarnation of the Disney Channel. It doesn't recieve as much priority or attention as its big sister, but does get its fair share of good content (Motor City, Tron Uprising, Kick Buttowski)
Nickelodeon is pretty deplorable. The poster-boy of Pinnacle "90's cartoons" now lives in its own shadow. Like Disney channel they capitalize themselves on bad sitcoms, but when it comes to animation they play the """"safe"""" route, and boy does it destroy them. It seems like Nickelodeon's plan of attack is to milk out SpongeBob and Fairly OddParents till the cows come home. Everything else is just half heartedly pulled out of their rear end. It appears that the mentality of the corporation is that kids want over the top cheap gross out humor. That was true at one point... but only for a different time period. A few Show creators have confessed that they refused to work with Nickelodeon because the lack of creative freedom given. That's rrreeeaaaalllyyy bad for your company. Some respectable animations that they have made recently though include the Avatar Series and the most recent incarnation of the Teenage Mutant Ninja Turtles.