Overlong? Certainly, Over ambitious? Maybe, Muddled? At times yes... but all these flaws ultimately seem less important than the stunningly effective narrative that unfurls with absolutely no punches pulled.
Its a time of huge change and the morality of Hollywood at an all time low. Margot Robbie gives a stellar performance as Nellie Le Roy, gifted the break few if any would be starlets will ever get, only to totally blow everything up around her. Brad Pitt gives a pitch perfect portrayal of a silent era matinee idol unable to transition once sound arrives on set.
But for all its (to some) graphic nudity, sexual deviancy and outright Roman Empire levels of depravity, its also a love story. Both a love letter to a bygone Hollywood age but also a deeply moving story of two people drawn to each other like moths to a flame but only managing to damage each other in the process. The lead character Manny Torres played by Diego Calva is Oscar worthy. It reminds me at times of the truly mad intensity of the lead protagonists in John Fantes' novel that inspired Bukowski to write "Ask The Dust", a story coincidentally set in Los Angeles in another time period.
Its definitely a movie worth watching and as others have noted here, a film that will gradually find an audience and be seen as a classic after initially bombing so badly at the box office.