Just leaving a quick note, that Aseprite is looking really good since the last time I used it back in June 2015 (1.0.9).
It's the right balance between a modern feature set and nostalgic user experience.
I used Autodesk Animator heavily way back in the day, and aseprite feels like the natural extension of it.
I anticipate using aseprite again on a near-future project.
Thank you!