We just added our Savin copiers to Pharos so decided to go with the Savin PCL 6 driver. It seems to manage duplexing better across mixed machines. The queue can be released to 4 different Savin models, as well as HP LJ4250, CLJ4700,LJ2300. For MAC users, it's easier for them to set up with a generic Postscript driver, and we release the MAC queue to any printer or copier with Postscript.
We started using so many different drivers to fix various issues. Then someone one one of the Pharos forums mentioned that they use Xerox Global Print Drivers (GDP) . We installed it , it works well across HP machines. http://www.support.xerox.com/support/global-printer-driver/downloads/enus.html?operatingSystem=win7x64
Hope this helps.
Nashville State Community College