Turbo Fire seems more advanced than the Firm, allowing you to grow with it. I read some people that tested the new Firm were doing a few of the 20 minute workouts at a time. True HIIT you shouldn't be able to do for more than 30 minutes. There are a few 20-30 minute, and even a 15 minute workout in TF.
I think you can't go wrong with TF for an overall fitness program... but the Firm presale is a pretty good deal. It's hard to say how they compare to TF till people do them
Gotta pick a Christmas present...
