If you like fast; then you will like Sumatra PDF Viewer (or Reader). This viewer blows them all of the water when opening and viewing PDF files. Sumatra is open source (FREE), is simplistic in nature (not a lot of bells & whistles), small in file size (<1.2 MB), does not write to the Windows registry, and is available in a full install version (for on your PC) or as a portable version (for on your flash drive).
If you go the full install (setup) route on your PC, you can make Sumatra your default PDF viewer (or reader), in place of Adobe PDF. I actually uninstalled Foxit PDF Reader on my PC, another great PDF viewer, to give Sumatra the lead duty of opening PDF files on my PC.