Wondering if the Haaka 9’s are better in slush because of more space between blocks.
No doubt, the studded Hakka's are much better in slush than my X-ices, especially in deep slush where the Hakkas dig down and move it away instead of riding on top of it. Deep slush seems to be fairly rare, though, and you know when it's there and can adjust your speed accordingly.
Wet ice is where I think the studded Hakkas shine over the X-ices. Think a road with a couple of inches of packed snow on a day with a daytime high of 45 degrees and a low of 15. We see that fairly often in CO.
The studded Hakkas have fantastic grip on the ice on top of the packed snow, both cold and wet. The X-ice's don't do well with a layer of melted water on top of the ice. I suspect they are much better than all-season's, though I don't have any mounted, so haven't tested any.
Edit to add: With warming temps, it seems even more important to have winter tires, ironically. We've seen layers of ice in Denver due to freezing rain and melt and freeze cycles that we never used to see here, and those are just the conditions were studded tires are superior.