By all measurements, Teenage Mutant Ninja Turtles 1987 was a huge success. Its cartoon spanned 10 seasons with 193 episodes. That's a hell of a run.
It adapted the darker comic (which was a hyper violet parody of trendline in comics in the '80s, "grim and gritty") into a more kid-friendly, humorous tone. "Cowabunga!" "Heroes in a half shell!" and so on.
That's not to say it was "bad," there are great episodes from the beginning to the end of the series (but as it was, there was also a lot of bloat and bad episodes as well, the quality had wild swings).
And it had a HUGE cultural impact. Action figures! Cereal! Video Games! T-Shirts! A music tour! Movies! and more!