I use Izotope RX quite a bit, and like it a lot. The only other noise reduction suite I've used extensively is the Waves X-Noise series which is also really good. I find the Izotope plugins to be very comparable to the Waves, for lots less money. Plus, the Izotope RX suite comes with a spectral repair plugin/app that is the best I've used. Great for taking click bleed out, or other weird anomalies.