MacOSX: FastPreview [Space key] - automatically refresh, but has no zoom and other features. It is very useful to find file by preview.
Preview (default MacOSX application) - automatically refresh, preserve zoom, but not exact position of view. Acrobat Pro (full) - lock files, there is feature to one-click refresh file if only one file is opened. You may switch on in preferences "Restore last view settings when reopening documents". Acrobat Reader - lock files, there is feature to one-click refresh file if only one file is opened. You may switch on in preferences "Restore last view settings when reopening documents". There are dozens of commercial PDF editors in App Store, but I never tried them. Martin
