Given a relatively simple CSS:
Your example works as expected in Google Chrome, Safari (Windows), and IE8. The text breaks out of the 150px box in Firefox 3 and Opera 9.5.
Additionally
won't work for your example, as it will either:
work when word-breaking but when not word-breaking not display any hyphens, or
work when not word-breaking but display two hyphens when word-breaking since it adds a hyphen on a break.