Difference between ORC and RC files

[Ashok Kumar]

 Hi Gurus,
I am trying to understand the advantages that ORC file format offers over RC.
I have read the existing documents but I still don't seem to grasp the main 
differences.
Can someone explain to me as a user where ORC scores when compared to RC. What 
I like to know is mainly the performance. I am also aware that ORC does some 
smart compression as well.
Finally is ORC file format is the best choice in Hive.
Thank you