Awesome features:
1) Being able to take our collaboration to the next level with comments, notifications, etc. directly associated with individual mockups and access controls.
2) Archive vs. Active is a useful model to keep mockups around after exiting that mockup portion of the development lifecycle.
3) Prototype view!!!
4) Versioning. Propose alternate version.
Potential improvements:
1) More generous asset constraints.
2) Tighter sync between desktop and myBalsamiq. Something in the spirit of an interface in the desktop to easily navigate myBalsamiq project and mockup hierarchies and take a mockup offline to edit. myBalsamiq + iCloud. Don't forget easy syncing of assets. (A lot of our users can't get over no keyboard shortcuts.) 3) Site-wide BMML templates? Cloning works, but seems to only be within the current project. Work around seems to be download BMML and upload into other project.