PDF-XChange vs Sumatra PDF

Those wishing to View/Modify or perform simple editing and even OCR Image based PDF files on their Windows PC's now have a FREE pdf reader alternative to the Adobe Reader! The PDF-XChange Viewer is smaller, faster and more feature rich than any other FREE PDF Reader/ PDF Viewer/ PDF Editor available.
Sumatra PDF
Sumatra PDF is a free PDF, eBook (ePub, Mobi), XPS, DjVu, CHM, Comic Book (CBZ and CBR) reader for Windows. Sumatra PDF is powerful, small, portable and starts up very fast. Simplicity of the user interface has a high priority.