xmlslurper

I searched for a while on this topic and found some results too, which I am mentioning at the end of post. Can someone help me precisely answer these three questions for the cases listed below them? For which use-cases using XmlSluper makes more sense than XmlParser and vice-versa (from point of view ease of use of API/Syntax)? Which one is more memory efficient? (looks like Slurper) which one processes the xml faster? Case a. when I have to read almost all nodes in the xml? Case b. when I have to read just few nodes (like using gpath expression)? Case c. when I have to update/transform the