Has the issue with no Windows 95/NT drivers been solved when using 19200 baud mode? If I recall, that was the main hurtle for my use of the product. And 19200 baud was required to eliminate pointer lag when behind several KVM types. I recall there had been attempts to hack some Logitech drivers to get around this, but I don't know what became of this.
EDIT: I had a setup which let me use my Arduino to blank out the MCU so I could reprogram the unit, but I have since disassembled that setup so I'm no longer available to test alternate firmwares. I may have one blank MCU that I can still program, but won't be able to erase it again easily.