In response to the question as to why you would want to use GVies for PDF files, Martin told us earlier today that "in general, you would not do that because other viewers offer more features (e.g., bookmarks, links and Draw export) and operate much faster. There are, however, PDF files that no other RISC OS based viewer can handle. For instance, the text in some PDF files is displayed as random characters by !PDF and RiScript. GhostScript/GView displays such files without problems and is hence the only way to view them under RISC OS. In addition, GhostScript supports some advanced PDF features that the other viewers do not support, e.g., graduated fills."
Links:
GView 1.50
GhostScript (32bit)
!PDF