The one thing these 1960's Marvel superheroes cartoons have over the latest Marvel cartoons is that they are more true to the comics. They take little creative liberties with the source material and Iron Man has that comic book feel. The animation is sparse but that was likely intentional to emulate the comic book.
Don't listen to the other reviewer that says that Iron Man's theme song is cheesy. He then says that the Spiderman theme song is good. Lets compare the songs, Iron man has the line "Tony Stark makes you feel, he's a cool exec with a heart of steel...". Spiderman has the line "Spiderman, Spiderman does whatever a spider can. Spins a web any size, catches thieves just like flies....". I fail to see how Spiderman's theme song is any better or less corny than Iron Man's. Both were sung by the same people and in similar style, so it makes little sense to say Spiderman's song is great and Iron Man's isn't. Now since that nonsense settled, check out Iron Man it's worth checking out at least once. It did the comic justice.
