b-quiet is pretty good. I've heard FatMat can smell for a while, though. Most of the Dynamat alternatives are very similar. Dynamat has pretty much the best recipe on their mat, that's why they have a patent on it. Whichever one you can get the best deal on, go with it. Just make sure it is made to work on upside down surfaces and see if you can get the temperature rating, especially if it's going on the trunk lid. I think Dyn. Ext. has a rating of about 300 deg or more, don't quote me on that, though. If it's rating is too low, it might start to peel off when it gets hot.