I absolutely adore Cirque Du Soleil (CDS) shows and have seen most of them.
A general tip for most CDS - get seats a little further away from the stage. Not only will you save a load of $$$, but you actually get a much better view! IMHO when you sit close to the stage you are missing out on the bigger picture, as there is a lot going on.
I will certainly rank Ka as one of my favorite CDS shows. I have seen La Nouba, O, Mystere, Zumanity, La Reve (although not part of the Cirque Du Soleil) and a couple of traveling Cirque Du Soleil circuses.
The storyline of Ka was easy to follow and struck a cord with me. The twin imperial siblings, main protagonists of Ka, follow a journey filled to self-discovery. I loved the mix of martial arts, acrobatic feats and technology advances. Most acts were performed on two giant moving platforms, and at times it seemed that the performers magically defied all laws of gravity. All acts seems effortless and executed perfectly.