Ok, time to bring out the heavy hitters for each side...
Phoenix (Jean Grey, any incarnation) Vs Ion (Kyle Rayner, first ION incarnation)
Both of these characters have power beyond most other characters in their respective universes so i'll give you a quick rundown of their powers ok?
For a brief period, Kyle achieved godhood as Ion, when he absorbed the leftover energy in the sun after Hal Jordan sacrificed his life in the Final Night limited series, energy which had merged and grown with energies released after Oblivion's defeat.
With his new powers, Kyle could bend time, space, and reality. Kyle could even be in many places at once. Kyle's trans-godlike powers had drawbacks: Ion was one with everything, but Kyle Rayner could no longer sleep or separate himself from the overwhelming responsibilities.
As Ion, he has god-like powers. He's able to project himself in dozens of different places at the same time and has a limitless amount of energy. One version of him is working at his art job, while another delivers meals to poor people in Uganda and yet others are in places such as Mexico City and London stopping crimes. Kyle is even off-planet, on the planet Tendax (where he visited with Jen in issues #138-139), which is still in the middle of a civil war. Kyle puts a stop to the fighting, acting as a sort of guardian over the whole planet. The biggest problem that Kyle has is that he can't sleep.
Kyle also uses his powers to make changes for his friends. He restores Jen's genetic powers so she is once again Jade and no longer needs aid of a ring. Kyle also uses his powers to break the mental barrier that John Stewart has placed on himself causing himself to be paralyzed.
Having new power levels, Kyle finds himself more and more detached from 'normal' people. When he's single-handedly able to stop an alien invasion, Superman intervenes and informs Kyle that he needs to back down and allow others to help. After awhile, Kyle agrees to stay in the background. He then utilizes his power to scan the planet, finding his father in a matter of minutes (Kyle only had a faded photo of his father and almost no memories of him). After having a face-to-face with his father, Kyle uses his time-travelling abilities to scan back in time to when the various men who became Green Lantern (such as John Stewart, Hal Jordan and Guy Gardner and even himself) first got their rings.
Quick Powers Rundown
Reality Altering: Nigh-Omnipotent ability to manipulate Energy, Matter, Reality and all it's constituant parts.
Chronokinesis: Nigh-Omnipotent ability to manipulate time.
(Kyle ION details taken from various sources on the net)
The Phoenix can revive, absorb, rechannel, and preserve the lifeforce of any kind of lifeform, meaning that she can take life energy from one person and give it to others, heal herself with the same life energy, or even resurrect the dead, since the Phoenix is the sum of all life and death.
As Phoenix, Jean's powers escalate to an incalculable level: allowing her to rearrange matter at a subatomic level, fly unaided through space, survive in any atmosphere, and generate massive destructive blasts and atmospheric disturbances. She manifests a "telekinetic sensitivity" (called "the Manifestation of the Phoenix") to objects in her immediate environment that lets her feel the texture of objects, their molecular patterns, feel when other objects come into contact with them, and probe them at a molecular level.
When she engages her Phoenix powers, Jean is surrounded in a flame-like energy corona that takes the form of a large bird of prey. As the Phoenix, Jean can resurrect herself after death and is unaffected by the passage of time.
The Phoenix's power could tap into the energy provided by life-force reserved for future generations, thus denying them existence. It can wield this energy to project beams of immense concussive force. It can transmigrate throughout time and space by folding its energy back into itself, causing it to collapse akin to a black hole.
It then reforms itself upon reaching its destination. It can directly absorb energy such as Cyclops' optic blasts or the entire energy of a sun. It is also capable of absorbing the energy and life-force from a foe. The Phoenix Force can control life and death itself and is the Guardian of Creation.
As it is the nexus of all psionic energy, it has mental abilities of cosmic scope, including telepathy and telekinesis, and often seeks out hosts who have strong enough psionic abilities so they will be able to withstand the force's power, such as that of Emma Frost who could not bear the burden of Phoenix when it bonded with her. When the Phoenix Force enters a host, a fragment of its powers is left behind when it leaves. Even a small fragment can be stronger than an unexperienced host using the Phoenix's powers, as seen by Rachel Summers, who had full access to the Force, but her opponent threw moons at her with only a fragment (the Phoenix Force decided to not interfere with mortal beings and only allowed Rachel to tap into the force's powers at that time).
When bonded with a host, the Phoenix Force amplifies their abilities to incalculable levels. It can manipulate matter on a sub-atomic level (e.g., turning wood to gold, stone to crystal, etc). It can teleport others across vast distances across space and can also open wormholes to access corners of the Universe. If the Phoenix Force is harmed or killed, it will form an "egg" of cosmic power, incubate in the White Hot Room, and hatch out completely healed.
(Again, Phoenix details taken from various sources on the net)
ok peeps... time for the big throwdown... Ion Vs Phoenix...
do we have a winner or is there even a reality left by the end of the fight?