Only problem with SimpleXML is that it needs to have the complete file in memory. This isn't a problem for small XML files. But reading a file of lets say 100MB will produce tons of objects an thus a large amount of used memory.
I'd argue that any chance of having a large XML file where you'd use SAX, you'd need to deal with JSON in the same manner. Then the problem is solved with XML (use SAX), but with JSON, what do I use?
