Pro: they avoid starting another instance of the JVM for each "command"; they run on Windows. Con: they are grotesquely bloated for humans to read and write;

Pro: they avoid starting another instance of the JVM for each "command"; they run on Windows. Con: they are grotesquely bloated for humans to read and write; (as indicated elsewhere) they make any custom file generation "tasks" a PITA. Personally, I'd like to strangle the bastard that invented Ant :-) It would have been so much nicer to have just copied make syntax, and predefined a few macros for java-specific tasks which actually spun off threads within a JVM based interpreter.