My LGS had one in the showcase I got to check out today. The new Sandman X is much lighter than the Sandman S with some neat texturing on it. Its also HUB pattern with a removable keymo, at least the one I looked at. It appears to be an improvement. I don't see me replacing my Sandman S but if someone gets to shoot one with some real life feedback, maybe. The biggest takeaway was the weight and not dedicated keymo. Hope this helps someone looking. I still hold that the Sandman S is one of the best hard use cans on the market for all round functionality.
