I wouldn't say they sound dead. They are about like a nickel wound but not as bright as a stainless steel string or something like ProSteels . They don't sound bad on a fretless, and sound good on a fretted. I just do not like the feel of them.
One medium set I had sounded really good at the beginning but died rather quickly....something freakish for a coated string.
D'Addario manufactures the strings that Elixer's parent company uses to make their strings. D'Addario also makes their own set of coateds, which sound as good to me, and are somewhat cheaper as well. You may want to check them out.
FG