What are the advantages of jailbreaking?
I'll give you two reasons that I jailbreak.
Welcome to convenience! Move your important toggles directly into Springboard where they are always available instantly even while other apps are running.
Notification center integration ios5
Customizable drop down window
Show date and memory on statusbar
Many themes available
Many 3rd party widgets available.
You can swipe the statusbar to bring down the main window. You can configure in activator settings other methods of opening the SBSettings window. You can integrate into ios5 notification center using notifications in settings app. Customize it to your liking!
This is way better than the stock text message app. With this you can reply to texts without ever having to exit a game, safari, whatever it is you are in. Plus you can set up activator buttons to open the app without having to actually go to the homescreen and open the app. LINK
These two things here are enough for me to jailbreak.
I also like being able to install and customize themes instead of the stock layout that comes on an iPhone. Also you have tweaks like folder enhancer which allows you to put as many apps in a folder as you want. You can even put folders inside of folders if you want. Then you have a tweak called Zeppelin where you can customize your carrier logo. Like with AT&T it will say just that at the top of your screen, but with zeppelin you can add logos. In previous jailbreaks I have resized SEC logos and sent them to posters on here so that they can have their teams logo at the top of the screen.
Here is a screenshot of when I had my 4S and it was jailbroken. I was running a custom these called pages and I had the TuskWear logo as my carrier logo.