Most would argue that Mighty Mouse is just a derivative of better creations, namely Mickey Mouse and Superman, but I believe he's a case of 'more than the sum of its parts'.
Mighty Mouse has a personality all his own, adventures that are very singular, and an evolving history. This character has been around for a while, and with each iteration, he grows more and more unique.
I loved it as a kid, and even still as an adult.