Off-Brand Dynamat

Hey, I was wondering if anybody out there knew of a site that reviewed sound dampening products, or had some experience or suggestions. What makes me ask this is that I saw some off-brand stuff on ebay that was the same price as the 36 sq ft pack of dynamat, but it had 100 sq ft in it.

I'm really looking for some nice sound dampening here, but would also like to keep it relatively light and thin...

Any comments or suggestions out there?:frown: