[Eclipse]

Yes it's stock, and rooted. Although What are the pros of changing the rom?

Touch wiz is gay for pretty much everything but the note series. A custom rom gives you an experience that's simply unattainable with stock.

Cons: You'll need a custom recovery which will trip the knox flag and void your warranty. Updates are more frequent but nightly updates can be buggy.

Cyanogenmod is my favourite rom.