While the FTDI cost more (around $6.00 with the regular USB port, less with mini USB for Arduino), they have the advantage of being able to be programmed so they can work with other third party aftermarket programming software.
You can also do this same procedure with an FTDI FT232RL USB UART board. As the Sil Labs drivers are built into Windows 10, there are no installation hassles.
We've found the simplest solution is to remove the PCB with the Prolific chipset out of your existing cable, and install a one dollar Silicon Labs CP2101 USB TTL UART in its place, a procedure that takes about 5 minutes. Update 2016: With Windows 10 now on the landscape, I'm told that once you have the Prolific driver (described below) successfully installed and working, Windows Update likes to overwrite it, and you're faced with doing this procedure again subsequent to the update.