First of all I would say sorry to those who like reading complete reviews as my review will disappoint them.
To keep it very simple and sweet I would say OSO is worth a watch provided if you like watching movies without asking many questions, the first half is excellent where farah khan has taken a dig on lot of actors and directors of 70s and that too brilliantly, watch out the scene where SRK tells to deepika (dosti mai thankyou or sorry nahi hoti) and behind him you will see young sooraj barjatya copying his dialouge on a piece of paper.
Unfortunately the second half is disappointing, (though there are few scenes worth watching specially the filmfare scene where the actors and directors made fun of themselves."watch Subhash ghai and akshay kumar and you would come to know what I mean".)apart from few scenes like this the second half has not much to write about .
Acting by the cast is decent but as usual its SRK stealing the limelight from others.(no marks in guessing this)
Music is good and the direction of the songs do equal justice, specially the om shanti om song with 31 stars.
But at the same time there are downfalls too, the biggest of them are the lack of emotions specially if you are choosing such a subject. (if you have seen karz and karan arjun you would understand where farah khan had failed to deliever.
Forget all the hype and watch this movie without any expectation and you may not come disappointed, if nothing atleast you would say" time pass ho gaya".
CHEERS!!!!