Yes it works. I have used it on some tracks, but I find I don’t need to bother after sorting cabling- the biggest last sibilance-killing piece were the Silversmith Fidelium speaker cables, I found they removed some remaining sibilance I didn’t know was there.
It is very handy to use, along with the other DSP functions such as room eq.- you set the program on the remote, store it, and then simply press the button 1-9 to employ the setting. The next track doesn't need it, hit the remote button again to remove DSP's. You just have to remember which button does what.
The D’Esser, like analog mode, is a mod and some people like and others just hate the concept.
Similar to tone controls. Funny though, how many of these same people’s favourite recordings have already been mastered/remastered using Weiss pro tools, and perhaps the same "mods" they claim they hate.