Going from SolidWorks to NX:
Usually, this is easiest because the workflows are so similar. Dassault Systems (SolidWorks) licenses its main Parasolid kernel from Siemens PLM, owner of the kernel. The main core of SolidWorks is the same kernel as that of NX.
Going from Creo to NX:
The workflows are different, but our experience working with companies has shown us how to communicate & translate quirks & features from Creo into NX.
Going from Catia to NX:
The same goes for Catia; it’s a different workflow, but again there are always little usability things we’ve encountered to smooth the way.