Depending on what you wanna do with the phone, rooting is a great thing. After rooting, which is a necessary step to an unlocked boot loader... You can modify just about anything. If you're not already a member, create an account on xda-developers. And nowadays they have made rooting so easy. After reading so I knew what I was doing. It took about 30 seconds.
Once you're rooting you have access to many programs. You can over/underclock the processor. There's one I use called adfree, it gets rid of the ads in the free versions of programs. One popular one is GMD autohide. You won't need it be a use you have a gs4 with actual buttons... but on the G2 with the navbar on the bottom taking up some of that 5.2" screen, GMD hides the bar and you can bring it back with small swipe from the bottom of the screen.
There are definitely perks to rooting, but the main reason people do it is so they can unlock the phone. They you can flash custom Roms, mods and kernals aimed at performance or power adjusting to prolong battery life. Take a look at cleanROM. It preserves all the stock functionality but debloats the phone of all the preinstalled carrier crap. Then my preference is Nova launcher on top of that. I also flashed a couple files on my phone to get rid of the "Verizon wireless" on the lock screen, as well as, remove the 4g logo when I'm on WiFi and the am/pm from the clock... cleans up the notification bar up top.