Pros/Cons of jailbreaking my iphone 4s?

I have the latest version of iOS 6, I've never jailbroken anything before. I've read how to do it, but I'm still kinda scared that something will go wrong and I'll have to get a new phone. I read somewhere that I should restore it before jailbreaking it? I really don't want to do that. Will jailbreaking it erase my pictures/texts? Is the stuff on Cydia free?

There's no downside to jailbreaking download evasi0n and jailbreak it you won't lose anything