Add the following lines:

set JAVA_OPTS=%JAVA_OPTS% -Dswing.aatext=true
set JAVA_OPTS=%JAVA_OPTS% -Dswing.defaultlaf=com.sun.java.swing.plaf.windows.WindowsLookAndFeel

just after the line

if "%JAVA_OPTS%" == "" set JAVA_OPTS="-Xmx128m"

in groovyConsole.bat. The first line turns on text antialiasing and the second turns on the Windows Look And Feel. You can do the same in all the other .bat files as well. You may find the antialiasing doesn't improve the appearance of the fonts very much, in which case remove it.