XML view or JS View?

Hi,

Which one is better?

1) I am having a single js view. The same view I am using as creation, display and edit screen.

    I am able to achieve it through js view easily. The only issue I see here is that my js view has functionalities. So the complete functional logic is not in controller.

2) What if I use XML view instead of JS view. What would be the advantage if any, if I am using XML view for my requirement.