According to the developers, the 1.0 release took around 18 months of work and involved the rewriting of over 20,000 lines of code and the addition of 6,000 unit tests. Performance was the focus of the 1.0 development and version 1.0 is now described as a "performance beast". The developers recommend SproutCore 1.0 to anyone who has considered SproutCore, but was waiting for it to be more mature.
The next release of SproutCore will benefit from the work done in 1.0 which has laid down the groundwork for new features. Version 1.5 "(or whatever it's called)", will probably be available in the summer.