I understand what
Rukbat is saying but let me play
Devil's advocate for a moment.
Personally, I would not consider an unrooted phone as I would find it far too restrictive. Rooting allows you SuperUser access to change virtually every aspect of the OS.
For instance, rooting allowed me to install stock KitKat on my phone 3 months ago and I do not have Knox Security or a locked bootloader on Android 4.4.2. It allows me to install de-bloated ROMs that remove Samsung and carrier bloatware, saving up to 1GB. I can use custom kernels with a choice of governors and schedulers for performance or battery saving and to overclock/volt to, say, 2300 Mhz for gaming, or underclock/volt to 1134 Mhz for battery life. I can configure almost every aspect of the look and feel of my phone. If I want to improve my signal, no problem, I just flash a different modem. If I need, say, a desktop clock whilst the phone is charging I can incorporate one. It also means that in a matter of minutes I can do full mirror image backups, nandroids, of my phone's OS and files and restore them just as quickly. I can switch from JB to KK and back again in no time. I can even extract certain elements such as SMS and save them as well as having multiple backups of apps and their settings available to me. I can access the system area of the phone for instance and change my boot animation or insert my own ringtones and alerts directly into the system folders. I can change the look of contacts or my dial pad without having to download loads more apps as these modifications can be inserted and run at system level. So much so, that all my Play Store apps are now easily accommodated on the internal memory with 6.5GB of space to spare. The list of things that you could do goes on and on. For instance, I long ago, as most rooters have, dispensed with Kies as there are other, more reliable, methods open to us for firmware updates, backups and storage.
However, there are caveats... theses things do not happen overnight and you need to read, read, read and research, research, research, before embarking on these sort of changes and understand what you are doing. Be aware of Knox security, the Samsung flash counter and how rooting may affect your warranty. Above all, understand that with SuperUser access comes the ability to SuperUser screw up! There is one line in almost all of my Dummies Guides...
"Flash in haste... repent at leisure!"