I haven't seen anything indicating Prolific has a problem with their drivers. Where was that posted? I'm not counting the above statement.
That is a good point.
There is a $4 eval board from TI with an ARM CM3 on it (or is it a CM4). It also has another chip which is the same sort of USB to UART which can be broken off of the rest of the board and used separately. I wish I had incorporated one of these into my test fixture so it just had a USB port on it. Heck, if this board had been around when I designed my test fixture I would have just added the entire module as a daughter board to control the FPGA. Well, more likely I would add something like the rPi or Beagle Board at this point, but maybe not. Hard to say. I doubt if I will roll my own for a low quantity system again.