The best value for the moeny will be the product that does the most amount of dapming with the least amount of material.While products that come in rolls are pretty cheap, they will also require many more layers to get anything close to the same results that a quality cld mat will get you.
See, products that come on rolls are tapes, designed to go on roofs. No way around it. Company buy roofing tape in huge quantities, then sell it online and rename it XYZ sound deadening.. or whatever.
These products are sometimes asphalt, which is dangerous to use, and usually have a very thin foil (or mylar backing which is worthless) which is not nearly enough to constrain (the "C" in CLD) the adhesive.
As a reasult you need A LOT of the product to do a good job. Using one layer of this stuff WILL reduce vibraions. Don't get me wrong. Anything you glue to the metal will help to SOME degree. How much it helps depends on a few variables. The better the product you use, (thicker/stronger foil, better adhesive, higher elastomeric value etc) the less of it you will need.
Products that are designed to reduced vibrations, product that are designed to be constraint layer dampers from the begining come in sheets, not in rolls.
The foil is too thick to roll up comfortably and adhesive is usually 50%- 100% thicker that the roofing tapes. The thicker adhesive means more elastomeric value between the foil and the metal which means better damping performance. All this equates to less material per sq foot required.
So, if you are asking what is the best VALUE mat on the market, there are a few great options. But the answer will always be:
The one that allows you to accomplish your goals with the least amount of material for the best price.
Do a search on these products
Second Skin Audio
Dynamat Extreme
Raammat BXT II
Hushamat
Stinger Road Kill Expert
SDS CLD Tiles
That will get you headed in the right direction
ANT