Slate Digital FG-X (Virtual Mastering Processor) by drewwebsteraudio
The FG-X is the best mastering processor I have used to date. It can get the mixes very loud while maintaining a dynamic feel.
It has two sections. A Compressor and a Leveler.
The compressor is very transparent. It helps tame the mix before the final leveling stage.
However, the leveling section of the FG-X is the part that makes it great. It has LoPunch and Detail transient knobs that allow you to adjust how it will react to low and high frequency transients, mainly the kick and snare. Turning the knobs up lets the transients attack more, thus making the mix much more punchy.
It also has a dynamic perception knob, which what it does is right in the name, and it works really well. It also has an ITP slider (Intelligent Transient Preservation) that allows you to adjust between Hard and Smooth transients. I have mainly used it for aggressive styles of music and the Hard ITP settings work really well. All the transients of the drums and even the guitars hit really hard, making the mix feel very punchy and dynamic.
Another great feature is the "Constant Gain Monitoring" button. When enabled you can adjust the gain as much as you want, but the output volume will stay the same. This will save you from getting tricked into thinking the leveler is changing the sound when it's really just making the mix louder.
There are a couple downsides, however. The leveler section is very CPU intensive, so you may not be able to use it in-session if your computer isn't powerful enough of if your session already has a lot going on.
Also, unlike other plug-ins, the FG-X isn't one where you can just install and use it successfully right away. You really need to read the manual to get the sound you want, but it's an easy read.
The price is also a little high, but it does something I think a lot of other plug-ins don't do: Makes your mix loud while maintaining a dynamic feel.
Overall I would definitely recommend this product.