Does anyone have any experience in using this pulg-in? Does it work? Is it worth it?

Evidently is has no users, so I suppose that tells me something.

I have never heard of this before, so I cannot comment on it and how it performs;
all I can tell you is that I am using Nik DFine for removing noise and have found that this is maybe the best tool for that job that is available;
I have used NeatImage before but found that NI removes too much detail sometimes IMHO;

in combination with more subtle noise reduction measures you can achieve amazing results with DFine

Never used DeNoise before. I do have other Topaz products that are terrific. I think DeNoise is a relatively new product too. When I was looking for a tool that reduced noise the two most popular addons were Noise Ninja and Noiseware. -I went with Noiseware and have been pretty happy with it.

Personally I use Lightroom 3's noise reduction, and as it does everything I need at my level, haven't investigated further.
I do hear good things about the Topaz products.

Cheers

James