I rebuilt my Liberty Bell chimes with the PBR kit, and the end result was much better than expected. I'd agree it's not quite as good as Gottlieb, but not nearly as bad as I expected from what you usually read.

Alternatively, if you have your spinners pretty juiced, consider just unplugging the chime unit. The sound of score reels turning over at lightspeed when you rip a spinner is a great sound in itself, and is unique to these late-70s Williams EMs.