Transformers fans tend to be long-term devotees, though - people who fell in love with the toys and the characters back when they were originally coming out, and stuck with them over the years. The Turtles, on the other hand, tend to have a bit of a broader base, I think - you've got your die-hard fans from back in the day, and then you've got your younger fans who've been watching the more recent series and reading the comics. I could be wrong, of course, but that's the way it seems to me.