Review (4/5): It does work.
In order to get it tightly on to any hair dryer, it's a 2-person job. That said, I would not get it if you're someone who wants to take your diffuser on and off repeatedly (like me) for sometimes smooth and other times curly hair. If you have a second hair dryer and are willing to dedicate it to your diffuser, pick one up. That's what I did.