At first glance, it may seem an obvious choice. Superman! Flying, orbiting the earth whenever he feels like it, super strength... what's not to love? Yet, Superman doesn't really know what it's like to be human. He has a purpose in life and lives that purpose without question. He may be Earth's protector, but he's always an outsider, looking in.
On the other hand, for all of his teenage angst and guilt, Spider-Man is very human. He questions himself constantly. And in that questioning can find answers to help his life work better. In that way, Spider-Man is like all of us. Constantly searching for understanding -- constantly trying to find fulfillment and meaning in our lives.
Superman has it all figured out. He's Earth's protector. He doesn't need to question his purpose, it's clear to him. In a way, Superman has blinders on. He's not searching to be his best self, he already has his answers. It's a very singular vision of his purpose.
As people, we tend to be more multi-layered than that. Spider-Man is human. He has real life responsibilities, problems, joys. He examines his motivations from within. And when you examine from within, you gain a better understanding of yourself and those around you. So where does that leave us? Would we rather be perceived as "perfect" and have no need for others to contribute to us? Or would we rather keep exploring to gain better understanding of all that life has to offer?
I guess we each get to choose. For me, I'd rather live a life that's been fully explored. Superman can have his perfection. I'd rather stay open to new insights and self-awareness. By continuing to explore all of life's possibilities we also are open to people contributing to us, and their contributions (along with our own insights) can lead to a fulfilling and rewarding life.