Lets compare and contrast the 2 Justice League movies. Justice League: Mortal was a movie that went into pre-production in 2007 and was to be directed by George Miller. It featured a young Justice League facing off against Maxwell Lord. It was put on hold due to the Writers Strike in 2007/2008 and was eventually put on an indefinate hold and was announced by Jeff Robinov that they would look to make a team up movie after the individual movies come first.
Justice League will go into pre-production around late 2012/2013 for a 2014 release date. It is rumored to be directed by Batman film series creator Christopher Nolan, along with the rest of the Batman team (Jonah Nolan (Screenplay), Emma Thomas (Exec. Producer), David Goyer (Story) and Hans Zimmer (Music)) and will include the Green Lantern, Superman, Flash and Wonder Woman movies into the same unvierse.
Lets compare the cast firstly: (As Justice League 2014 hasn't got a full cast yet, I will include who I think will be a proboble candidate) Also the age is when the movies would/will be released ie. in 2009 for JLM and 2014 for JL.
SUPERMAN

Justice League: Mortal - Actor: DJ Catrona
Age: 29
Credentials: Skin, Windfall, Love is the Drug
Justice League - Actor: Henry Cavill
Age: 31
Credentials: The Tudors, Immortals, Blood Creek, Stardust
BATMAN
Justice League: Mortal - Actor: Armie Hammer
Age: 23
Credentials: Billy: The Early Years
Justice League - Actor: Christian Bale
Age: 40
Credentials: Batman Begins, The Dark Knight, Terminator Salvation, Equilibrium, American Psycho
WONDER WOMAN
Justice League: Mortal - Actor: Megan Gale
Age: 34
Credentials: //
Justice League - Actor: Emily Blunt
Age: 31
Credentials: The Wolfman, The Devil Wears Prada
GREEN LANTERN
Justice League: Mortal - Actor: Common
Age: 37
Credentials: Smokin' Aces, American Gangster, Wanted
Justice League - Actor: Ryan Reynolds
Age: 38
Credentials: Green Lantern, X-Men Origins: Wolverine, The Amytiville Horror, Blade: Trinity, Van Wilder
FLASH
Justice League: Mortal - Actor: Adam Brody
Age: 29
Credentials: The OC, Mr & Mrs Smith
Justice League - Actor: Scott Porter
Age: 34
Credentials: Friday Night Lights, Dear John, Prom Night, Bandslam
MARTIAN MANHUNTER
Justice League: Mortal - Actor: Hugh Keays
Age: 62
Credentials: Mad Max, Farscape
Justice League - Actor: Laurence Fishbourne
Age: 52
Credentials: Matrix, Matrix Reloaded, Matrix Revolutionis, Predators, Mission Impossible III
AQUAMAN
Justice League: Mortal - Actor: Santiago Cabrera
Age: 31
Credentials: Heroes, Camelot, Empire
Justice League - Actor: Phiilip Winchester
Age: 34
Credentials: Alice, Crusoe, Thunderbirds
Now let's get to the stories:
JUSTICE LEAGUE: MORTAL
Superman investigates Maxwell Lord who has build up an army of OAP's. When he attacks Lord's island, Lord takes over his mind and uses him as a weapon. Using Superman as his primary weapon, Lord used Superman to attack cities around the world and the worlds heroes gathered to stop the unstoppable Superman. Batman, Wonder Woman, Green Lantern, Flash, Martian Manhunter and Aquaman manage to break Superman free of his spell and then go and stop Maxwell Lord's invading OAP army.
JUSTICE LEAGUE
As it has yet to go into pre-production, the story is unknown. I would say 70% of fans want to see Darkseid and his Apokolipian army invade earth. There could be hints of his in "The Man of Steel" tying it with the Superman movies, it would be an interplanetary war with Superman, Batman, Wonder Woman, Green Lantern, Flash, Martian Manhunter and Aquaman against Darkseid and his army.
The Directors:
JUSTICE LEAGUE: MORTAL - Name: George Miller
Credentials: Happy Feet, Babe, Mad Max
JUSTICE LEAGUE - Name: Christopher Nolan
Credentials: Batman Begins, The Dark Knight, Batman 3, Inception, The Prestiege, Insomnia
What do you think? Which Justice League would come out on top, the kindegarden Justice League featuring the 90210 casting or the hard core, gritty Justice League under the leadership of Christopher Nolan.