Dunno if UML has been "ported" to zSeries or not. That would clinch it. Most of us feel the same as you do. Personally, UML is a great project. But z/VM offers things that are significant in the most positive ways, things that UML just cannot do, even if it has been ported: hypersockets, non-Linux guest interaction, hypervisor interaction (CP commands).
So handle it delicately. Tell your UML afficionado that UML is a good thing but that z/VM offers different qualities of service from UML. Others have tried to document the advantages of z/VM. You would have to weight those lists agains the UML feature set and elimiate overlap for a better UML -vs- VM comparison. -- R;
