Is an iPhone better 'jailbroken' or not 'jailbroken'?

I just got the iPhone 5 and I keep hearing about 'jailbreaking' iPhones to be able to do a lot more things. So my question is: Is jailbreaking an iPhone bad? What kind of cool things can I do if I jailbrake it? How do I jailbrake it, if its a good thing?

NOT jailbroken. Hacking slows the programming and messes up everything.

I was all hipped to jailbreak my phone and I finally got a program to do it! And I don't really see the big fuss about it cause it seems like I wasted my time. Maybe someone can give you an answer that will excite me about my phone. I did a lot at first and things just weren't turning out how I wanted so I gave up an figured I would do it when I had more time to play with it.

It is now illegal to jailbreak a phone