I will make a blanket statement and say that if your school is in
this thread, you probably shouldn't bother rushing unless you are Selena Gomez or someone amazingly famous. Not only is your chance of getting a bid small, you need to lay out quite a bit of $$$ for registration fees and appropriate outfits. If you've got it to burn, that's your prerogative.
However, if you're at a school where people can sign up the first day of rush, the fee is miniscule, and lots of people don't even think about pledging till they are sophomores, I would say go for it.