One selling point with Cirque Du Soileil is that you can see real live people performing extraordinary and precise physical feats. Half of that translates pretty well to 3D filmmaking, I suppose, though something is lost watching these kind of DON'T BREAK YOUR NECK stunts in a recorded, edited medium.
On the other hand, their dream land fantasy stuff may well get a boost from cinematic interpretation. We'll see.
Here's the first trailer for the Cirque du Soilei film Worlds Away 3D. It was directed by Shrek and Narnia alum Andrew Adamson, who also wrote the screenplay – though it remains to be seen how much of a screenplay there is, and to what extent it adapts the circus' live shows.
And here's another, Japanese trailer for the film that has been hiding online for a few days.