I have both workouts, have just previewed the BC one, and have done the KB one (the two workout combo). I really liked it!
Be aware, though, that Kelly is not a particularly good cuer (she rarely repeats cues for moves--like hook, cross, up, hook, or whatever--which I personally would like her to do, and she sometimes isn't clear, like calling crosses 'punches,' or calling a 4-punch combo that's not the regular jab-cross-hook-up but a bit different, merely a 'punch combo' and not spelling out the punches).
On the other hand, her choreo isn't complex. Viewing the tutorial before doing the KB workout is a good idea, as she previews all the moves there.