I really like the idea of more competition to the software market (free or paid for that matter) so I welcome this.
I took it for a spin and whilst it still feels a little rough around the edges, it does what you expect it to do. However, what really turned me off was that it was not very "rapid", unfortunately. You can see it in the video above as well, when you pull a slider, the visual feedback isn't instant but rather it updates every second or so.
Especially when fine tuning colours, I fond this difficult to work with. But maybe they can get it a bit more responsive and I would happily give it another spin.