Sorry, but if you see no speed or quality gain, you should better clean your glasses.
I had it both running during Betatesting and the quality and speed improvements can be very heavy.
Possibly not if you are using 9pin needle printer, but on modern printers.........
I made every print on both ghostscript versions and there is a difference, especially on the render engine, dithering and color.
There was a print on a glossy paper, which i later send to the programmer, that was so impressive, everybody wanted to have one from me.
Speed improvements are heavy for example on using Finalwriter97 and PS: output.
