Quasar Versus Green Lantern
Quasar: Wendell Elvis Vaughn, a good-hearted native to Wisconsin, trained to be an agent of S.H.I.E.L.D. His lack of a killer instinct kept him from anything more prominent than guard duty, but saved his life when he put on the Quantum Bands, powerful weapons whose rampant energies killed every previous wearer when they grew too aggressive.
Green Lantern: Hal Jordan served in the military as a test pilot. A dying alien handed him a ring.
Quasar: Eventually, after roaming the universe, Quasar discovered his true role as protector of the universe. The bands around his wrists could never be removed while he was alive, but could tap into a limitless zone of energy.
Green Lantern: Hal was not the only Green Lantern; there was in fact an entire corps, with representatives posted on nearly every planet in the universe. Hal was the Green Lantern assigned to Earth, but not the only one. Alan Scott, though not a member of the corps, preceded him. Others to hold Hal's post include John Stewart, Guy Gardner, and Kyle Rainer(who took over after Hal went nuts and killed the corps because he was upset someone destroyed his city).
Quasar: Died, had a villain cut off hims arms in a futile attempt to remove the Quantum Bands, saved the universe while in a body composed of energy, and was restored.
Green Lantern: Destroyed the D.C. Universe and tried to recreate it according to his whim. Was defeated, later sacrificed himself to stop an alien from draining the sun. Became the Spectre, eventually came back to life and got his old job back.
Quasar: His Quantum Bands allow him to fly. He can create a shield of energy around himself and carry an atmosphere, allowing him to travel through space. He can “teleport” by leaping in to the dimension that is the source of the bands' energy, and reemerging anywhere he chooses in normal space. The limitation to this is that within an atmosphere, the Quantum Jump wreaks havoc, so it's best used in space. Quasar's bands can drain energy from his foes, and he can create objects from them. They protect him from psychic manipulation. He can bend light around the bands, so no one notices them on his wrists while in his civilian guise.
Green Lantern: The ring must be recharged once every 24 hours. A Green Lantern can fly and create objects out of green energy. A Green Lantern cannot teleport, and the ring is useless against the color YELLOW.
Quasar: Wendell was once marooned in the New Universe, where he acquired The Star Brand, a tattoo that gave the bearer unlimited power. It eventually burned out when he returned to the Marvel Universe.
Green Lantern: After killing his former bosses and fellow Corps-members, he absorbed all the energy from the main lantern. He used this energy to destroy and rebuild reality, and burned it out in his final sacrifice to save the sun. I'm unclear as to how he's returned and how anyone would trust him with a ring again. Perhaps a current reader could clear this up.
That's how these two heroes stack up. Both have weapons that manipulate energy, that allow them to fly and create any object out of energy that they can think of. Anyone can wear a ring, and the ring is removable. The Quantum Bands stay on until the wearer is killed, and it takes a certain kind of personality to control the energy being filtered through them. The Q-bands have no weakness to color, and the energy they process is generally yellow, something a Lantern's ring is vulnerable to. A ring has to be recharged; the Quantum Bands do not. Quantum Bands allow Quasar to teleport himself through space and anyone or anything he chooses. He could maroon his opponent in deep space; on one occasion he even left a foe in the trackless void of the Quantum Zone. Quasar is one man entrusted to do the same job it takes an entire corps to do, and he's done a much better job of it.
In conclusion, it's easy to see why Quasar is the clear winner, and why I have no life.