Thanks for all your time and effort Skunkape! So I just wanted to clarify a couple things:
I have a fully stock (never rooted) brand new S3 from Sprint that has received the OTA (over the air) update to Jellybean.
----Is there anyway I can root the device and still keep the actual stock rom that is on the device without flashing any new roms (whether it is the stock or custom rom---b/c I'd rather change as little as possible on the phone besides allowing root access)?
----Also, if I root the device, will I have to worry about future OTA updates unrooting or bricking my phone?
I basically am attempting to root the phone for myself and 3 other people (all of whom have no experience with rooting devices), and I would hate to have a bricked phone 24-48 hours later
Rooting your phone using this method does not reload a rooted rom. It does nothing but install the custom recovery and and superuser on your phone. So you actually have the same exact files on your phone.
It is a common misunderstanding that being rooted will store you from getting ots updates. This is not entirely true. Custom recovery and removing bloatware is what causes the ota's to fail.
This is easy to beat if you're not planning on flashing roms themes our mods.
1. Install titanium backup pro and never remove the bloatware. Instead just freeze it. The apps will not run. When you receive an update you just need to defrost them and your back in business.
2. Custom Recovery is a different story. But still easy to overcome. You can reflash stock recovery using your custom recovery at anytime you want.
3. A second way to defeat the custom recovery is by editing the team epic root from recovery zip file. Samsung added a script file that looks for the stock recovery file and if it's not there, it will reload the stock recovery. Team epic root from recovery renames those files so the script doesn't run. Therefore your custom recovery won't be replaced by the stock. But the zip file can be modified so that the files don't get renamed and stock recovery will automatically be rewritten.
4. Lastly, root may very well be lost during an ota. However there are things you can do that may not guarantee it won't happen but does minimize it a bit. Both ota root keeper and SuperSU will save your root in a backup and even hide or disable your root during the ota process. Thus minimizing the risk of losing it and making it easy to restore if you do.
Worrying about ota's is the worst possible excuse for not rooting your phone. During the first day of the jellybean update, I had multiple ways for everyone who wanted to update to update. Even people on custom roms and custom recoveries were able to get updated to jellybean during the very first day. Long before 95% of the people waiting for the update to be pushed through the ota.