The difference that I know between casting latex and neoprene that I've ordered from Chicago Latex, is that Neoprene is a rigid casting material, somewhat the consistency of leather when pulled from the mold, later hardening further to a rigid plastic form, and casting latex remains much more flexible. Therefore I've never used casting latex...but then we may be talking about the same thing, since neoprene, as marketed by Chicago latex, is actually a latex material. There may be no difference at all.