Hi...the gym that I go to recently started offering these classes in January. You do the same exact routine in each class for about 6 weeks or so and then you learn a new one. It's pretty similar to a standard kb class--lots of different patterns with kicks and punches. There is one "high intense" segment that is thrown in maybe 2 or 3 times throughout the class that's lasts maybe a minute or so.
Overall, it's a decent workout. Not too intense in my opinion, but I suppose that depends on your fitness level. Honestly, I've only gone to a few classes because I get easily bored doing the same routine.
Hope that helps!