Back in the good old days of Nick, this was my favorite show, alone with Rocko's Modern Life, Hamtaro, and Courage the Cowardly Dog. Why ever people hate this show is beyond me.
It seems that a lot of people hate anime because they are simply being cartoons. That's really why its great. The show is random, but not to random so it stays interesting.
The shows characters are are the strongest I have seen from any cartoon. I can't think of any weak characters. Unlike most cartoons made within the past two years, Kirby's characters are not one-dimensional and flat. The viewer gets to see many sides of Tiff or Tuff or any major character.
The show is just genius. I just wish the show could have been more popular. Unlike most animation now, this show can be enjoyed by the whole family. It makes a good kids show, yet it also has a strong appeal to a more mature audience. Truly one of 4kids's classics and one of their best cartoons.