After reading this article and other articles about the different types of attic insulation, I am leaning toward the spray insulation. My problem with the fiberglass batts is that they are so difficult to work with in the close places and around objects as mentioned in this article. The batts are also terrible to clean up if you ever have a major leak in the attic.
The blown insulation sounds like it has many good characteristics, but I do not like that it can be blown about, and as the article says, the particles could enter the duct work. With the spray foam you can easily spray the insulation on the sides and on the top of the attic ceiling where the foam will stick. Also, you do not have the same worries about moisture damaging the insulation with the spray.