DOM parser loads entire XML document in memory while SAX only loads the part of the XML file in memory.
DOM parser is faster than SAX because it accesses complete XML document in memory.
SAX parser is suitable for large XML files than DOM Parser because it doesn't require much memory.
DOM parser works on Document Object Model while SAX is an event based XML parser.
Prefer DOM parser over SAX parser if XML file is small otherwise use SAX parser if you dont know the size of XML files to be processed or if it is large.