I just finished installing new speakers and sound insulation. I went with the edead from Elemental Designs and Infinity Reference speakers in front and back. I am very impressed with the sound deadening. If you are considering doing this cheap mod, let me tell you...DO IT!
I bought 60ft2 of edead v1 and that was plenty for 4 doors in a double cab. In fact I have about 1/3 of it left. I put a single layer on the inside of the outer shell and another layer on the inner shell. I'm so impressed with the results I'm considering doing the floors. The speakers are great too, but the real difference was with the sound insulation. I wasn't looking for a high power sound system, but rather a modest improvement. I figured while I had the door panels off I might as well add some sound insulation. I was extremely pleased with the results. So again...do it.
As far as edead vs fatmat vs dynamat? Who cares? edead is on the cheaper side if things and I have no regrets. Just put something up there. I'm glad to answer any questions.