Sounds like you're aiming at teams and small ad agencies? Is that correct? I do like the idea of being able to share the versions as it progresses with other stakeholders. That is valuable. I didn't grep that from the demo. Admittedly I didn't poke around too much, I spent a few minutes on the site.
Is this for web design teams or mostly traditional media teams (Packaging, branding, print)? If the former, how do the developers work with it? If the latter, I like the functionality you've described.
I apologize if these questions and my critiques are too early in your dev cycle, I realize that you just released this (And it does look well polished!). I really just have an interest in this space and would like to see something work for my needs.