The previous X-Men Origins entry, for Colossus, got such bad reviews I didn't even bother to pick it up- specifically, it wrote in a backstory for Piotr that completely missed the point of the early years of the character to the point of doing actual damage.
Sean McKeever, however, stays in much safer territory with Jean Grey's issue, expanding on her established background from a black-and-white story in Bizarre Adventures #27 that most current readers probably don't even know exists. McKeever sticks to telling the story of Jean's traumatic telepathic awakening, adding just a little extra to what we knew to provide a sense of resolution. He wisely avoids amping things up with unlikely elements or trying to tie Jean's early years into the Phoenix mythology. It's a simple tale well told.
But the real reason to get this issue is the artwork. Mayhew's cover is nice, but his interior artwork is also painted and is superior throughout. Not only does everything look wonderful, but his storytelling skills are more than up to the challenge of showing us all the things here that happen in Jean's head without major action scenes to drive them. He captures Jean's expressions of withdrawl, excitement, fear and hope wonderfully, and for such an emotionally-centered story, that's exactly what was needed.