PDF has a worldwide standard viewer (Acrobat Reader) and most people have it or can get it. TIF can be viewed with thousands of programs, so supporting people who are trying to view your document with some off-brand TIF viewer can be difficult over the phone.
PDF (as plotted from Pro/E) is a vector format. This means you could suck it back into other software and make a DXF out of it. We do this with vendor-supplied decal drawings. PDFs can also contain raster images, but not from Pro/E. TIF will always be raster which can limit your future flexibility.
Neither one will be searchable for text that appears on your drawings. This is a limitation of Pro/E. If and when Pro/E supports text-printed-as-text instead of text-printed-as-lines, PDF files would be searchable, while TIF files would not.
Both TIF images (2-bit) and PDFs can be extremely small (filesize).
Personally, I prefer PDF, but many others prefer TIF.
Thank you for your insight. I just run some tests- created both pdf and tif out of the same file. 63KB the pdf, 58 KB the tif. Both look good when printed, but if you zoom in (like 500%) there is a difference in quality: PDF is much better.
Brian: what would be that software you reffered to to create dxf's?
For importing drawings into other programs like Word, I've had the best results with CGM files. It is also a vector file, reasonably small size. I use Larson CGM Software’s WebView CGM viewer to look at them. You can not import PDF files into Word or any other MS Office product and TIF files vary greatly in size and resolution depending on the settings used to make them. I do use TIF files for shaded output.
For general viewing, we use PDF exclusively for all corporate documentation. I prefer to plot to postscript from Pro/E and use Adobe Distiller to convert to PDF. Much better output than printing directly through Adobe PDFwriter.