I like a good melamine. Haven't used Juma for ferrules but guess i'll give it a shot. Don't care much for micarta. Tried the melamines Atlas sells (most of the white stuff with weave) & they are ok but porous & a lil soft. Tried their Titan & it gave a nice hit but was pretty brittle. Tried the XTC & it was soft & unnatural feeling. Antler is actually my favorite but again, the color. Consistency is also a factor. Antler ranges too much in hardness. I don't care for ivory though it's popular. It all has it's pros & cons. Just depends on what you like in terms of feel. I really like old fiber ferrules & most folks can't stand them. Personal taste. I even like PVC & ABS. Ivorine4 is actually about the only stuff I think sucks pretty much in every aspect. It's ugly, hard to work with, heavy, and in my experience gave a dead feel.
Much will depend on the tips you like, too. Certain tips work well with certain ferrules. It's a science and pretty fun & interesting to dabble in. Get some different ferrule materials & different tips & try different combinations. You'll be amazed at what you find. Like tuning an engine, the dynamics can vary tremendously with the tiniest of changes to formula.