Hey, I'm Freddy, I work with @Xarbrough at Nementic Games.
In addition to his feedback, there's one small thing I've noticed: In the sync view, only the incoming and outgoing branches are shown. In classic Plastic, the actual changesets are displayed in addition to the branches. Not sure if this is intended or not.
Also, I'd like to be able to use the mouse scroll wheel to scroll through the branch explorer.