First I’ll give my own answer
You should go with PCL 6. Here’s why: You don’t need PostScript. If you did need it you would know it and you wouldn’t be asking this question. PostScript is more problematic than is PCL, so if you don’t need it it’s better avoided. It’s more problematic in these ways and more: harder to find drivers (for a Win ME computer for example), more resource hungry (both on the printer, the workstation, and the network), HP’s PostScript drivers are going to be much buggier than their PCL drivers, the quality of HP’s PostScript emulation (that is, a third-party clone of Adobe’s PostScript program) is highly questionable whereas the PCL is an HP product and therefore a better risk, PostScript tends to throw obscure errors when printing and requires obscure expertise to troubleshoot (very frustrating)-PCL does this less, PostScript tends to run the printer out of memory easier, PostScript drivers offer lots of obscure settings that are useful only to industry pros (like color separations, e.g.) and will only confuse normal people and give them more ways to cause themselves problems, and on difficult prints PostScript will often be slower. All that off the top of my head.
PCL6 is a powerful page description language and will do anything you ever need to do. Quality is not an issue, PCL works fine and can print the same vector graphics and vector fonts as can PostScript. Photos and other bit mapped graphics are outside the realm of PostScript’s power and thus the two languages will print them the same, except that PostScript will render the photo in text and blow up its binary size, thus taking longer to download it to the printer (it has to do this because PostScript is a language of text, there is nothing binary there. Everything is rendered into text characters).
PostScript offers many advantages, but mostly to printing industry pros. An example is that if you want to print something on a super-high resolution image setter at some local high end printing shop they will likely accept the file only in Adobe Photoshop or PostScript formats, thus if you are using the PostScript driver you have a way to make such a file. However, PDF format can be used now in many situations where PostScript was formerly required. PostScript drivers do tend to offer more features than the PCL driver and some may be useful to you (like Booklet printing e.g.) but at this late date and age it’s more likely that the PCL driver offers everything you would ever need, and the PostScript driver may not offer much at all extra that you could use.
