In comparison with the original Series 0, the S4 is actually a tad thicker, 0.2mm or so, but we shouldn't notice that at all. I mean, 0.2mm ...Getting the 44mm. I have worn the original AW, but revisiting and try it again with series 4. While it has gotten big the AW$ is thinner. isn't it? Anyway i'll try the 44mm and if doesn't work out I can always exchange for a 40mm.
I'll go for 44 just because of my old bands (for 42mm) that will fit