On-screen GUI for intuitive adjustments.
The key to grading with curve controls is to ensure that the range of control is designed to work well with the linearity of source image.
Ranges designed for video or log images
Nattress Levels and Curves controls have special mapping for video or log images to ensure you get a fine degree of control with your curves.
Mapping for Cineon and digital camera log formats
Video based images are placed into a specially constructed film-log space which also gives you the benefit of film-like contrast handling
Resources
Larry Jordan's tutorial in this excerpt from his webinar 'Apps & Plug-ins for FCP X'.
John DiMaio's review Nattress Levels at Production Apprentice.
CiniDigital's Spanish video review
Steve Douglas's nice tutorial on Ken Stone's Final Cut Pro website.
Requirements
OS X
Lion
Mountain Lion
Mavericks
Yosemite
Final Cut Pro
Versions 7 and 10
Motion
Versions 4 and 5
Adobe After Effects
CS5 - CC 2014
Adobe Premiere Pro
CS6 - CC 2014
FxFactory*
*Required to run this plugin. Download free