We use the KIP plotter, and make use of PLT files for electronic files and then use the powerprint software to convert the PLT to a PDF, or for sending print sets to the printer. These files are also our in-house copy of what was issued.
We have (finally!!) been getting requests for issuances of DWF (using the Eplot pc3 per sheet) for electronic files, and sometimes we don't. Can we make a pdf from a dwf?? We have the reader that came with the ACAD CD. I'd teach myself to fly before we purchase anymore software, we JUST got 2006!