[Spoilers about for both JLA: World Without a Justice League and Justice League Elite (the whole series).]
JLA: World Without a Justice League functions, rather strangely, as something of a sequel to Justice League Elite; at least, if you're a big fan of Manitou Dawn (all two of you), this is the trade for you.
As the final trade of a JLA series once headlined by Grant Morrison and Mark Waid, there's a terribly disappointing lack of reminiscent nostalgia here, though that may me determined more by the Infinite Crisis-inspired JLA meltdown than the author's sense of closure; it doesn't help that Tom Derenick's art, though a good choice for this mostly Green Arrow-centered story, remains not my cup of tea.
Ultimately, World Without a Justice League boils down to Batman, Green Arrow, Black Canary, and Manitou Dawn trying to stop the Key from murdering everyone in Gotham, with Envy of the Seven Deadly Sins complicating the process. When you consider that Manitou Dawn cheated on her husband with Green Arrow, Green Arrow cheated with another woman and ruined his relationship with Black Canary, and Batman dissolved the Justice League in part because of Green Arrow's decision to mind-wipe him, the interpersonal dynamics do have the makings of a powerful story, and in some ways it works; but considering the little-to-no relevance this story had to Infinite Crisis as a whole, ultimately it comes out feeling a little short.