I don't know. But I do enjoy the size of the 4S I have. I do wonder how long it will take me to get used to the 5S - if there is an adjustment period at all.
I played with the Galaxy S4 in the AT&T store and despite it's larger size, I found it to work well enough in one hand.
I had the same experience. While some people will say the iPhone is perfect for one hand, I played with the S4 and HTC One and both were fine in my one hand. Lets not forget you have stretch with one hand now with the i5 due to the height increase.
It's all perception. People will believe what they want to believe.