I've been doing Tae Bo for about 8 years and I'm a big fan so I always buy these new Tae Bo DVD's as they come out. This is the second from the 'AMPED' range that I've tried out (the other being 'Jump Start Cardio' - not as good as this one).
Anyway, it's true that you don't need the Amplifier resistance bar to do these exercises but if you've already got a lot of Tae Bo DVD's I would say that there aren't really that many new moves in this one and you may find that some of the DVD's you already have are a lot better in terms of producing a more fun and varied workout.
One thing I've noticed is that during this workout, the sets are a lot longer and the routine is therfore more repetitive than I'm used to with workouts like 'Tae Bo Bootcamp'. The other thing is if you buy the Amplifier bar, whilst the slow repetitions feel great in terms of sculpting the body, the fast repitions can be quite dangerous. I've had aching fingers and wrists as a result of some of the speed rounds. The Amplifier bar is a nice idea but it also doesn't translate very well to some of the old moves and I think the DVD is really lacking some original moves created just with the Amplifier in mind.
Overall I would still give the workout 4 stars: just because the power rounds are there, doesn't mean there's anything stopping you from continuing the slow repitions if it feels better - I certainly think this is very good for scupting & toning. The workout also keeps your heart rate up consistently which is good if you're looking for a cardio workout. It's a pity there was no floorwork at the end of the work out though as this would have made the DVD far more worthy of receiving the 4 stars I've given it!