JCR is good for working with Tree structured data (like RDBMS is good for table data)
for example you can copy, clone or move a subtree of nodes using Session (javax.jcr.Session) object
you can use query api over nodes,
in JCR you can query nodes using SQL like commands and XPATH commands
this is the same XPATH used for XML DOM operation and of course it is better for tree operations.

www.day.com/.../Query.html

if information was not enough tell me to describe in more detail

can you please tell me a little more about your project?
I am interested to get to know more about companies using JCR in Iran.