" "O" and Mystere is completely different, and there will never be any similar productions in Cirque du Soleil."

That's true.

I have to defend KA though, it's by far my favorite Cirque show (I have seen five, 3 in Vegas and 2 of the touring shows). I loved the story and was on the edge of my seat the whole time. The battle scenes were fantastic, and the double-baton routine, though it is by far the simplest act in the whole production, is probably one of my favorite circus performances I've ever seen, and is definitely my favorite object manipulation performance in any show, Cirque or otherwise. I thought the way they use the vertical stage was very clever, and the whole teepee turning into a flying machine thing was really cool. And the scene when the ship sinks was astoundingly beautiful. Although KA is the most expensive of the Vegas Cirque shows, of the three in Vegas I've seen (O, KA and Mystere), it's the only one that I would pay to see again. I haven't seen LOVE or Zumanity though.

On the other hand, a lot of what I loved about KA had to do more with the set and the performers interactions with it, and the amazing stage pictures. It was directed by Robert LePage, who is well-known for theatrical/operatic spectacles, so I guess that's not much of a surprise. Mystere's acts were really more focused on the prowess of the performers. There's a cube act that's astounding, and the chinese poles and the bungee/trapeze act were highlights for me as well. I guess Mystere felt like a collection of different acts, whereas KA was more of a unified whole, and I liked that about it. In that way Mystere is more of a traditional circus show, whereas KA is more like a theater production with circus elements in it.