Use of key/keyref - any best practices? warnings?

My organization is going to start looking at the use of key/keyref. I 
haven't seen many questions or recommendations about the use of this 
feature. Is anyone really using this functionality? What sort of problems 
(if any) are you finding? Is this functionality well supported by the tools 
and vendors - or is this another one of these features they are not 
implementing?

Thanks for any help you can provide.
..dan
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Danny Vint

Specializing in Panoramic Images of California and the West
http://www.dvint.com

voice: 510-522-4703