Flux is built from the ground up to be the best cinematic editor for Unity, focusing on performance, usability, determinism, and extensibility.
Note that from Flux 2.x, it will only support Unity 5 given the big changes in their animation system.
Animation Workflow (v2.x)
Timelapse Video (v1.x)
Not only it can be used to create cut-scenes (aka sequences), but also set up complex UI animations, letting you better control what is done when and making it much easier to tie with sound and particle systems. All this without needing to add a line of code!