What is better? A feature film, short film, or an indie film?

I'm reviewing auditions that i would like to go to and the movie
auditions say one of those film types. But the thing is, I don't know
the difference AND I don't know witch one is better to choose. please
help, I am using www.starsearchcasting.com and there doing free
auditions for only 4 more days so it ends June 26, 2011.
REMEMBER: also please tell me the difference between them it's really
important

Thank You:) ,