The Guardians of the Galaxy are Marvel's premier space-faring super-team intent on protecting peoples across our galaxy from the various cosmic threats that loom over them. Peter Quill, aka Star-Lord, is the team's leader, and he has led the Guardians through several scary universe-ending threats in his tenure with the team.
However, this isn't the original Guardians of the Galaxy--the original team is from the 31st Century (it's complicated), and their leader is Major Vance Astro. He was born in the 20th Century, preserved by a containment suit that keeps him alive. He's armed with Captain America's shield and leads his team against the threats posed by the warmongering Badoon.
10 STAR-LORD: Laid-Back And Easygoing
Peter Quill was an easygoing guy with a sense of humor. He isn't a leader that is going to ride his team hard or chastise them. He understands mistakes are going to be made; the goal is just to make sure everyone gets out alive. Plus, he's open to suggestions from the crew. Star-Lord is not a leader who is going to make you feel bad about yourself unless you actively betray the team and get someone killed.
9 VANCE ASTRO: Psychokinesis And Trained Fighter
Unlike Star-Lord, Vance Astro has the ability to generate telekinetic blasts that allow him to disrupt enemies' minds and even hurl them back. He was also a member of the U.S. Air Force and was trained in hand-to-hand combat. He's shown significant physical prowess in his time as a Guardian of the Galaxy--which stands in stark contrast to Star-Lord's reliance on luck and improvising.
8 STAR-LORD: Ragtag Fighter
Star-Lord is used to improvising. For a while, his Guardians of the Galaxy team was constantly changing, shifting, and, well, dying. He fought Annihilus, the Phalanx, Thanos, and the Cancerverse with whatever crew he had available. He doesn't lay down and give up, and he knows how to make do with the people and equipment he has at his disposal at the time.
7 VANCE ASTRO: Cap's Shield
There is just something about that shield. Major Vance Astro wields the shield of one of Earth's greatest fighters and heroes, Captain America.
This is a symbol of a freedom fighter that has survived for hundreds of years to still be used by Vance Astro in the 31st Century. He holds an artifact from a living legend and knows how to use it as a symbol that will lead his Guardians of the Galaxy to victory.
6 STAR-LORD: He Can't Stop
The newest Guardians of the Galaxy run by Al Ewing and Juann Cabal shows what else distinguishes Peter Quill as a leader and a hero: he can't stop. Even when he can lay back, relax, and enjoy the good life, Star-Lord feels compelled to go back out into the thick of it and save the galaxy from what threatens it--even if it costs him his relationship with Gamora, Groot, and Drax. Star-Lord needs to be doing something to help others.
5 VANCE ASTRO: He's Serious
Star-Lord, especially in more recent comics and in the films, has an issue with taking things seriously. He has to view most things through a lens of joking irony. Major Vance Astro doesn't have that hang-up. He knows that he is dealing with a serious situation that demands a sober view and a dedicated mind. He won't lean on the need to crack jokes to keep himself calm and is able to deal with what's around him.
4 STAR-LORD: The Sacrifice Play
Star-Lord has shown many times that he is willing to make the sacrifice play to save everyone and everything. The most notable instance of this happening is during the Thanos Imperative story. In the end, Star-Lord and Nova (Richard Rider) go into the collapsing Cancerverse to keep Thanos from returning to our universe.
They know that they won't make it back out, but they know it's better for everyone in our universe that Thanos doesn't return to rain destruction and bloodshed. Of course, Star-Lord and Richard Rider both returned, but that was only through several accidents of fate.
3 VANCE ASTRO: He Fought Michael Korvac
One of Vance Astro's missions with the Avengers came about when he traveled back in time with the Guardians of the Galaxy. The Guardians of the Galaxy and the Avengers teamed up to fight Michael Korvac, one of the most dangerous beings in existence. He is a godlike being with power unparalleled. He was able to kill the Avengers and the Guardians and was only defeated by himself. However, he resurrected both teams before wiping himself from existence.
2 STAR-LORD: They're Family
One thing that separates Star-Lord's Guardians of the Galaxy from almost every Marvel team outside of the Fantastic Four and, sometimes, the X-Men is that the Guardians are a family. They are outcasts from the far corners of our galaxy brought together by fate and the will to save the day. They rely upon one another and love each other. While Vance Astro's Guardians are close friends, they can't quite make the claim of being a family.
1 VANCE ASTRO: Fighting For Freedom
While Star-Lord knows what it's like to work up from nothing, Major Vance Astro and his Guardians of the Galaxy are fighting for the liberation of the human race. The Badoon Empire has enslaved the Earth, and the Guardians are the only hope left for humankind. Vance Astro is fighting for freedom, and that tends to inspire a certain kind of courage and commitment in a person.