I find that the bottom toolbar is harder to read now, and requires more eye-scanning to figure out what the different icons do. It's not as pronounced and grounded anymore. Also, the top navigation is less intuitive, and more subtle. I'm also finding information and text presentation to suffer as well. As much as I hated the beveled edges and skeumorphic design of the previous iOS, it was much easier to navigate. I'm sure companies and designers will work some of these early-stage kinks out of the interfaces, but I can definitely see a drop UI flow quality and information presentation with the move to this new interface design.