Hal and kyle anre green lanterns, but ion was the godlike omnipresent being that kylke became when he absorbed the remains of parallax's power and the power of oblivion. Parallax is NOT hal. Parallax is actually a parasitic energy being that is the personification of the yellow weakness and flaw of the green lantern power battery. GL's get their power from willpower, whereas parallax actually gets its power from fear, which is said to be simply another wavelength of the emotional electromagnetic spectrum that "the glow" is comprised of, and from which the guardians draw their power.
parallex is not hal, when did u find this out?{hmmm}
well anyway i dont know too much about parallex beeing this energy thing but if we are talkin about hal gordon as parallex against ion, id say that hal wins, even though he has less power then ion, still the whole power of the green lantern ring is based on the users will and mind, and we know for sure that hal is mentally much stronger than ion.