> ... In xpath2 you can have sequences of 
> > strings and sequences of text nodes (and sequences that 
> > contain both strings and text nodes) the rules for the two 
> > cases (and in particular whether spaces are automatically 
> > inserted between adjacent
> > items) are different on the two cases.
> 

We've removed some of the worst "surprises" in the light of experience, but
there will still be a few pitfalls for people who fail to realise the subtle
distinction between a string and a text node. The best advice for XSLT 2.0
users is: declare your types. Although you can still declare variables and
parameters without types, debugging becomes vastly easier if you do declare
them. 

Michael Kay
http://www.saxonica.com/