I tried several other maximizers and I can say Voxengo Elephant is clearly superior, it offers several ways to process audio depending on the material you are working on.
Elephant's sound is very clean, very professional and very stable.
I highly recommend this plugin. If you are accustomed to freeware maximizers and you think they have a good sound quality, then you MUST try Elephant! You'll hear the difference.
You will be able to go louder and still get a clean sound.
As for the CPU usage, it depends on the settings you set, you can use a light, yet clean settings to maintain CPU usage low and when rendering you can turn on all Elephant's features for a better mastering.
The documentation is very good, it covers all aspects of it, including explanations to help user to choose the best shape and speed values depending on the sound material.
I also think the price is more than fair considering the ammount of features Elephant offers, other similar plugins can cost as much as $600 not to mention hardware units.Read Review