I, too, have all three and like them a lot. I use Sharpen Ai on most photos. It takes care of a reasonable amount of noise as well as sharpening. I use DeNoise when sharpen does not take care of noise to my satisfaction. I only got Gigapixel recently and have not used it much. My primary use will be to improve extreme crops.

I use these as plugins to Affinity Photo. A decent computer is necessary to achieve acceptable speeds but I have not experienced any problem with speed. I would definitely recommend Topaz products.