Up until now, I have been using Visual Paradigm for modeling.
Visual paradigm support XMI for import/export but only version 1.0, 1.2, and 2.1 of XMI.
Steve opened an issue with compatibility between the Visual paradigm XMI and 2 other tools in the SPDX spec git repo: https://github.com/spdx/spdx-spec/issues/164
I don’t have any opinion on the model data interchange standard as long as it is a standard that supports UML modeling and there is a reasonable choice of tools which support the standard.
For 3.0, I am open to switching tools to GenMyModel.com it if simplifies the import/export issues. It looks like GenMyModel supports import of XMI version 1.1 and 2.0 (note the non-intersecting versions compared to Visual Paradigm).
As an aside, I find it interesting that as a standards group attempting to create a unified SBOM standard, we’re having trouble finding a standard interchange format for our UML model – a standard that has long been established. Hopefully, we’ll do better at creating interchange data formats between tools 😉