I used Second Skin. Used Damplifier Pro (dampening material) and Luxury Liner Pro (deadening material). I did the back wall, floor and all four doors and have enough left over to do the roof and I spent around $700 (including shipping) for all of it. Did it myself. Took about 20 hours, but the damplifier is peel-n-stick. The luxury liner needs spray adhesive for vertical surfaces, but no heat gun was needed.
All the reviews I read said that, for what you pay, Second Skin's products are better and cheaper than Dynamat.
I haven't used RAAMMat, but I've heard good things. Their sound barrier material isn't as thick as the Luxury Liner, but I think their dampening material is pretty good.