Mistika
Mistika is a high performance post-production software published by SGO. Although it has few users compared to its main competitors Autodesk Smoke and Flame, it has gained a loyal user base over the years, due to high performance, effective user interfaces (GUI, tangent devices and tablet gesture support and hotkeys), good stability, an open architecture(though the software core itself is not Open Source) and reasonable pricing.
Features
Mistika's main futures include timeline-based editing, color grading, compositing, image restoration, filters for stereoscopic finishing and native support for various media formats like RED and P2. All image processing is done on the GPU, which let's the user do tasks like grading 4k DPX files in realtime.
Criticism
The GUI of Mistika is quite different than most video editing software, and most people find it very different to understand at first. Although a lot of Mistika users spend most their time in the software (and therefore gets a deep understanding of how to do different tasks), this makes it hard for assistants, freelancers etc. to operate the system.