I've been a longtime fan of the Ninja Turtles for as long as I can remember. Over the last 40 years there have been a lot of excellent shows, and there have been a few REALLY bad ones. I initially thought this would be somewhere in the middle after seeing the commercials. However, I was pleasantly surprised by this one. It accomplishes what the predeceasing movie could not with flying colors (pun and reference intended). It took its time to explore the character of each turtle, which is ALWAYS appreciated. In addition to this, the show also does a wonderful job of expanding the world of New York City and the rouges within it. You will see characters from existing iterations return with Seth Rogan's spin to them, as well as be introduced to whole new characters that you have never seen before. SPOILER ALERT: While some of the new characters will seem a little boring in the beginning, you won't feel that way for very long.
While the art style will NOT be for everyone, I personally found it much better than the 3D style from the movie. It's colorful, scratchy, a little choppy (which actually compliments the many action scenes throughout the show). Love it or hate it, at least we can say it's better than TMNT 2012... (sorry not sorry).
It's a fun, action-packed, and even at times compelling cartoon that all generations can enjoy. It may not be the best, but it may be one of the best for me.