iZotopes plug-ins are awesome. I love Ozone - and their RX software is just slick. They truly are all in one plug-ins. But because of this, they truly are DSP hogs. Comparing a compression plug-in to opening Ozone and using its compression plug-in, I would rather use the single use plug-in if that is all I needed.
Friggin love iZotope - they put out good Mastering software.
And I like their harmonic exciter for bringing out areas of the spectrum or stereo imager for spreading a background.