Justice League of America: Omega collects issues #49-53 of Justice League of America and issue #1 of Starman/Congorilla (all originally published between 2010 and 2011). Like most DC hardcovers this one comes in unfinished black boards with glued binding. Extras are limited to reproductions of variant covers.
Like the previous volume of James Robinson's Justice League (Justice League of America: The Dark Things), Omega is poorly plotted and incredibly light on character development. Indeed, the characters featured here are one-dimensional versions of their usual selves--with the exception perhaps of Congorilla and Starman, who barely feature in the graphic novel outside of their single-issue story. The story's logic also borders on the nonsensical (if the new villain Omega is so powerful, why doesn't he use his power? where did the Dark Supergirl outfit come from? does Tangent Green Lantern's involvement serve any purpose except to supply the book's trick ending?).
As for the the Justice League art (by Mark Bagley and Pow Rodrix), it's pretty ho-hum. Thankfully, Brett Booth's work on the Starman/Congorilla story is outstanding. His figures are expressive, his layouts interesting, and his action sequences exquisite.
If you disliked Dark Things, you'll dislike this book too. The Starman/Congorilla story redeems the book a little; nevertheless, your money's probably better spent elsewhere.