right, quite fustrating really. Turns out this appears to be yet another difference in behaviour between 4.1 and 5.1... So, I just ran this same set of code against a 5.1 VCenter/ESXi host, and sure enough, it came back with values for the 'owner' column, and a few others, but not 'OS', as that is apparently already a property. Thanks LucD, for answering the question, though I sure do wish I would have got some sort of warning message returned from the 4.1 vCenter server..It happens to be where we have the bulk of our guests built...
Here is what it looks like with 4 of thos 5 custom attributes returned from the 5.1:
and a couple of the error messages thrown during runtime, as the above report was being produced:
