Provoc Grader is a compressor plugin designed specifically to be used on vocals.
The approach it takes is to allow you to apply the compression only to the part of the frequency spectrum that you want to target - this was you can keep as much natural dynamic as possible.
You can control the volume of Selected and Unselected bands, Input and Output level controls, and a Dry Gain control for matching the volume of the raw vocals to the processed output for on/off comparison.
This video provides a good overview of what you can do with Provoc Grader:
Changes in v1.3
- Improved GUI