ComponentOne Studio for Windows Phone is now compatible with the latest Windows Phone update 7.1 (AKA Mango). This update also includes massive performance enhancements for C1PdfViewer. The control now uses bitmap caching to render the PDF pages so user interaction is much more fluid.
Download the update here. You can install this over top of your existing version, or as a new install.
Also, be sure to let us know what you think on the forums. New controls and features await the next release!