DangerMouse will always have a place in my heart. If nothing else, it has one of the all time great theme songs. "He's the fastest, he's the greatest, he's the best!" Genius!
The animation was a bit limited and not overly impressive. But the character designs were iconic and top notch. DangerMouse with his trademark eye patch and Penfold in his little suit work wonderfully well.
For an American, DangerMouse also holds a unique appeal. The sly and absurdist British wit were a sharp contrast to the American cartoons at the time. I know I had never seen anything quite like it. There's also the fact that Americans are easily impressed with British accents, even on carton characters.
Surprisingly, the success of DangerMouse did not lead to more British cartoons on American TV. DangerMouse stands out as a sort of one-off success. It's the Monty Python of cartoons.
All in all, a wonderfully odd and engaging cartoon.