The Sketch comic is the rough outline/draft of the comic. It's much much further along than the color project and many things have already been changed between it and the color version, but the rough story is still there to be enjoyed. If you want a good long but sketchy read of what's in store for the future, enjoy the messy humble beginnings of Isla Aukate. There will still be a few surprises in store if you read both versions (as has already been seen).
The sketch comic updates every day (with more pages if someone sponsors one for $25). Happy reading!
Early access pages in the sketch version are usually one month ahead of the live comic.