Depends, on your money situation - $0.00 for an S3 is pretty nice and hard to beat, but it is an old phone. I have a rooted stock 32gb S3 with a 64gb card and I use it for everything and I am still happy with it - even with Touchwiz, it is still pretty quick.
I would have upgraded to an S4 myself, but Sprint didn't have a 32gb version :-(
If you can wait, maybe look at an S5 - although, if it is physically bigger than an S3/S4, I don't know if I could handle that size - because then you might as well go to a Note 3. But it gets down to how you use your phone. Dang, after reading what I just wrote, my answer is no help to you at all. I am a confused procrastinating dweeb.