Topaz Denoise has faced serious competition from the latest update of DxO Photolab to version 4. If you look through the forums, you will only find enthusiastic users who consistently declare it’s better than Topaz Denoise.
Unfortunately, I could only try it with external photos because I’m using Fuji X-Trans. And there the results were not better. But it seems that especially in the high-iso range better results can be achieved.
Maybe a motivation for Topaz Labs to rework the completely useless RAW module, probably an external library which Topaz Labs do not program themselves