spray on cellulose

[SilentSound]

Has anyone had any experience with this material?

http://www.spray-on.com/ProductInfo/...page=SonaAcous

I'm soundproofing and then acoustically treating a garage with a 2" concrete and 1/4" stucco(external..i'm just being specific)wall. I've ripped out all the old plywood leaving the longitudinal beams to the celing frame(spaced about every 1.25') and revealing the concrete wall which I'm looking to fill with a dense material that isn't sheet rock before I apply plaster board then appropriate acoustic treatment. I've seen a few references on this BBS to the spray on cellulose and read the specs on the site but am looking for a real-world experience from someone. That or any other cost-effective method. How much is this spray anyway? Thanks,

Matthew M