When I did my research I considered liquid products also, but I felt the application would be messier, and the biggest concern at the time was fumes - I'm not sure about e-dead, but the liquid products out at the time all released fumes as they dried. I don't remember whether the fumes were harmful or if they just smell bad, but I decided on the best "roll-on" product I could find. In retrospect, I think the roll-ons are pretty messy too, so if they've worked on the fume issue (or that is not a great concern for you - it was for me because i have two young kids), i certainly wouldn't rule out liquids if i had it to do over. You're right - roll-ons are just as permanent - plus you'll never want to take it off. You can't reuse it, and if it's covered by your carpet or interior panels, you pretty much forget that it's there.

Crager - unfortunately, with only 15 sq ft, you probably won't even be able to tell the difference. No doubt Dynamat is an effective product, but you need a lot of it, which is why a lot of us sought out comparable products for a lot less money.