There is no one compelling reason to jail break. Everyone is different and makes their own decision on whether to jail break or not. I, personally, jail break my iPad because of f.lux, SwipeSelection and iKeywi. As you know, f.lux "warms" up the screen at night so you aren't confronted with the blueness of the light. SwipeSelection allows you to swipe the keyboard to move the cursor versus having to use the magnifier tool. And iKeywi allows you a fifth row so I put my most oft-used characters right on the main keyboard (it's not updated for iOS 7 yet ... I'm anxiously waiting). With these three, the last two, especially, typing on the iPad is so much easier. As I said, no one can convince anyone to jail break if they don't want to. I just wanted to point out my favorites!
If you are interested in jail breaking, have a look at this Ultimate tweaks thread:
http://www.ipadforums.net/showthread.php?t=25824. It lists the most popular and we'll-liked tweaks of those on this forum. And no, being jail broken leaves your iPad no more susceptible to security attacks than a stock iPad. Yes, if you install remote access tweaks, you must change the iPad's default password (cause everyone knows it), but that is easy enough. If you don't install such tweaks, your iPad is a safe as a stock one. Of course, safe internet browsing applies to both, so one must always be careful there. Good luck making a decision and happy researching. Marilyn