Numerous tests have been done to show that the performance from the type of insulation you use in your wall varies very little from one insulation to another. The use of insulation is very important, no argument there, but the type of insulation used really does not matter as long as it is light, fluffy, and sized to fit the cavity (ie, R-13 in 2×4, R-19 in 2×6, R-19 or R-38 in a standard ceiling joist cavity). Compacting insulation, for instance R-19 in a 2×4 wall, can actually hurt performance as the insulation density will increase which will result in conduction between the insulation and adjacent framing/drywall. Specialty insulation does have its place in construction for various reasons, increased energy efficiency, fire rating, easier installation, no chemicals or less chemicals, and to avoid the dreaded itch from fiberglass.
Our Advice: Save the cash on the fancy insulation and put it towards products that will provide a much larger boost in performance. Or if you are working on a home theater, get a nicer sub. 
