I don't like Mason much either, but that's definitely an interesting interview approach you've applied there ;-)

The ability to stream output is very handy indeed, since it allows the important bits of a page to display even if a component breaks along the way. Well, depending on how you've got error handling set up, but you get the idea. There are plenty of little things like that which make Mason a good deal more pleasant to use. Then again, can't you do the same thing from regular CGI by setting $| to a true value? After all, your application is just sending to STDOUT.