[neatoman]

I think the best way to describe them is "Discount X-Men".

TMNT was more less spawaned from the X-Men and they do this day still feature similarities to the X-Men (even if the average Joe off the street might think TMNT is some weird comedy), the main difference is that TMNT doesn't really compare in terms of success. TMNT isn't exactly obscure but it's probably never going to have a movie making more than what the first Bay movie earned, it's never going to have as many movies as X-Men, it's never going to sell as many comics as X-men (not counting the Batman crossover of course) and it's not nearly as respected as the X-Men.

Oh and TMNT is never going to have a TV show as good as Legion, I think (given the current direction) that it only barely has a chance to top X-Men Evolution in terms of quality.