This app changed my way to build websites - especially web templates. I have heard about SASS, LESS and CoffeeScript before but this app was the reason why I had a closer look at those tools. Now I don't know why I ignored those great tools!
I have some minor issues with the app (e.g. changing the output of SASS files won't apply when working on an existing project) but I am sure those small problems are either because I still don't fully understand the app or they will be fixed in a future update.