Another useful PDF viewer to use with Scribus is GSview which is a graphical viewer/front end to Ghostscript. The latest version (4.6) with Ghostscript 7.07+ work very nicely together allow you to convert PS to PDF, as well as view and convert EPS, PS and PDF files among other tools. Version 4.3 is the first version to really work well under Linux (it was originally developed on another operating system). More details are in GSview and Scribus.
Xpdf 3.00 or greater versions of Xpdf from Foolabs will do a fine job of displaying and printing Scribus PDFs, including support for PDF 1.5. Xpdf also has command line tools for converting PDFs to PS. To get embedded fonts in all PDFs, not just Scribus, you should read the Xpdf man page about setting up the fonts paths correctly via the xpdfrc file. Otherwise, embedded fonts may not display properly. One known limitation is the inability to display transparency in Scribus generated PDFs.
For a taste of some of the cool PDF tricks Scribus can do, make sure you read through the sample docs located in the samples subdirectory of where the Scribus files are located. Maximize Acrobat Reader, open the file and follow the instructions. Consider it the first "Easter Egg" in Scribus.;)