Rupesh is an Adobe "scientist" (a cool word for CF Developer Engineer.) He was very active in listening to feedback from the original version of the code that was released. I, along with a few other developers, were in active discussions with him over issues with the first release. Thanks to Rupesh's hard work, he's addressed the issues that were discussed.
The biggest changes are the addition of being able to pass attributes to the CFTHREAD tag (which allows you to pass in variables who's values can't change,) threads having their own unique scope (so that variables outside the thread aren't negative affective,) and the addition of the thread.OUTPUT and thread.ERROR variables.
I really hope this POC makes its way into the core language. So if you're interested in making CFTHREAD/CFJOIN part of CFML for good, make sure to let Adobe know!