PDF-XChange Viewer provides a host of useful features to go along with superior functionality in letting you view and mark up PDFs with ease. The software will open PDFs saved on your computer or you can download them directly with the app. Navigating the PDF once its open is straightforward, as well, and there are many navigation and editing tools available on the toolbar across the top of the window.
The interface of this app provides a lot of versatility without over-complicating the layout. Just about every tool you need for marking up and viewing your PDF is displayed at the top of the screen. We were impressed that you can customize this layout to minimize clutter by selecting the tools you do and don't want displayed from the Tools' drop-down menu. Options include comment and mark up tools, link tools, measuring tools, and zoom tools. Navigating the document, itself, is quick and convenient, with multiple options for how pages are displayed and how many are on the screen at a time.
Commenting is supported and easy to insert and you can e-mail a document directly from the app as long as you have a compatible mail program installed, as well. Another convenient feature is the search box at the top of the screen that provides quick access to various online sources such as Wikipedia, Bing, Google, Yahoo, and others. Overall, this is a great product with an intuitive interface and lots of helpful features.