155w = less swing wieght because it is shorter.
158W - not going to be harder to press because the board is so soft, going to be easier to land jumps because you have more room for error, going to be faster on flats and downhill.
Hero is a soft board that has v-rocker, the v-rocker makes pressing and butters very easy.
I think but am not sure that the hero has scooped ends which also makes butters easy.
The 3 cm increase will give you a much more versitile board with very little drawback at your wieght.
Hopefully that cleared up my previous post.