Best deadener...
To me, this has always been somewhat of a paradox. First of all, most people look to sound deadeners to rid their vehicle of rattles. In that case, almost anything that takes up some of the tolerances between clips & panels will do the trick. Other people look to sound dampeners to lower road noise. If that's the case, most of it will be going on the floor anyway so sticking isn't a huge issue.
And here's where I get a bit confused; the best sound deadening usually is rather expensive. Spending $3-400 isn't out of the question. While it does make a difference and often does as it's advertised to do, my beef is that you can't take it with you. Call me cheap but spending a couple hundred bucks on something I cannot remove from one vehicle and place in another is an investment I'm hesitant make. That's important to me, it may not be to you. With that in mind, if I deaden anything I use the Home Depot/Lowe's stuff and take extra care with prep work. It makes a difference for the better and I have not had any horror stories with the stuff. Its performance more than justifies its price. I just can't see spending so much $$$ again on Dynamat, or the like, and leave it in the vehicle.