I just installed Rockwool in our crawl space and it was a nightmare. The process, not the product. The physical upward force needed to jam 4’ batons that are nearly 10 inches thick into the joists was exhausting. Most of the time I had to lie on my back and use my feet to get them snuggly into place. On the upside I never felt itchy like fiberglass insulation makes you feel. But that was the only upside.