Blur increases the render time. The blur came out grainy. The background picture is so interesting that I like it better without the blur. Perhaps if the wall in front of the castle wasn't blurred and the castle was slightly blurred it would work. The blurring should be done in a paint program so the render time won't increase and the grainy look won't be there. It could control what part of the picture you want blurred and how much. Cool table cloth and the glass, cubes, liquid and caustics look great. I'd love to see another render of your scene.