Juma is a thermoset plastic like bakelite, epoxy, and polyester. Bakelite is great, mine seem a bit softer than acrylic but won't oxidize like ebonite/vulcanite/Cumberland.
Juma is a little more brittle when working with it and also tends more on the acrylic side for mouthfeel. It won't oxidize but it is frequently less comfortable than ebonite or vulcanite.