I like the packaging design, I like that it's available in a bunch of colors, I like that you don't have to get messy dye-fingers, I like that there are different formulas for natural and artificial fibers, and I like that I can buy it locally from Oregon Art Supply. Before this, I had to special-order dyes for polyester and nylon.
http://www.dharmatrading.com/html/eng/5590684-AA.shtml
http://www.oregonartsupply.com/