I also have a parallel-port EPROM burner that I use more frequently, the Xtronics Pocket Programmer
At least their website is still active, and the latest Pocket Programmer runs off the USB port. Right now, I have no need for a $249.95 upgrade, but will keep it in mind.
Do you have a link to your preferred USB-to-ISA product?
For the record, I did find that the PB-10 would not necessarily run on newer (faster) computers. Maybe some of the internal timing has changed?