there's very little in it.
SIII - 136.6 x 70.6 x 8.6mm
OneX- 134.6 x 69.9 x 8.9mm
less than 3/4mm wider. you wouldn't even notice it.
Yes i wouldnt have any problems in getting it but the wider audience already thinks the HTC is too big, Heck some people think 4.3 is too big