I have been doing this series for a couple of weeks now. No, it's not a Cathe workout, but that doesn't mean it is not good. He is keeping the workouts simple, especially in the beginning. To ramp things up a bit, I use heavier weights and do more advanced moves (like a superman instead of cobra, or a plank with an arm raise instead of a regular plank). You do sweat, especially during Total Strength. He uses jumping jacks to rev up the heart rate between sets, so it is not so high impact. In phase two, it gets harder, and there are some extra dvds which you can order apart from the kit (should be available in the next month or so according to BB); I will buy them that way vs buying the deluxe, expensive kit. I usually tack on some short cardio or weight workout after, just to round things out. You don't have to. You do feel like you've worked your core.
I've really been watching my food since I started this, and I've dropped 5 pounds. I'm not saying it's all due to RevAbs, but it can't hurt.