This is a collection of comments made of various XML aspects by people who should know. At the end there is a discussion area for this community.
On XML processing
..DOM, SAX, and XSLT
These techniques have a distressing lack of unifying principles among them. Everything you might want to do with XML is available in one of the major approaches, but when what you want to do crosses the boundaries of what each technique does best, it is far from clear how to approach a problem. You are likely to wind up with a hodge-podge application in which various smaller transformations are chained together with heterogeneous techniques and tools.
from 2001 http://www-106.ibm.com/developerworks/xml/library/x-matters14.html
Our discussion area
It is my opinion that the lack of unifying principles stems from the born-in problems of "navigational structures". See OoLacksConsistencyDiscussion and NavigationalDatabase. -- A RelationalWeenie