> No, I do not have any examples; partly because I am 
> speculating instead of comparing implementations. However, an 
> RTF can be optimized for addition,  while a node-set must 
> allow fast traversal and direct (XPath-addressed) access. 
> Many RTFs are not used 
> as node-sets, thus this should make sense.

Ok, that's from an implementors point of view.  From a developers point
of view, converting to a node set is a pain.  Is it not possible for the
processor to initially use RTFs and then convert to a node-set
internally when needed?  Excuse my naivety here, but it seems the
obvious solution.

Does anyone actually do anything serious with an RTF anyway (without
converting to a node-set)?  Im scratching my head to think of an example
where the processor would be wasting processing time using node-sets
over RTFs.

 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list