This finding was somehow interesting:
http://hackaday.com/2014/02/19/ft232rl-real-or-fake/ . But the FT232 costs a lot more than a PL2303.
On-topic, I have a fake(?) serial adapter bought probably 10 years ago, same PL2303HX chip. But I haven't had to use it lately since I mostly use my BusPirate. However I needed to flash some board that needed 'variable baud rate' which the BP could not do. Basically it meant that the baud rate had to be changed in the middle of the operation from 19200 to 57600, on TTL levels. So dug up the old adapter, chipped the rubber housing away and soldered some wires directly on the pins to get the to the TTL signals. To do the job I ran the flash program under an XP virtual machine.
With that said I find out that work without a VM is virtually impossible - it is portable run it anywhere, runs any OS including strange Unix distributions used for specific tasks (car diagnostics, signal analyzers) and it helps with organizing stuff.
I have a VM for generic Linux stuff, one for matlab stuff, some images of my old harddrives that I can boot into with the workspace ready, XP VM for running iTunes, car diagnostics and viruses, a few of them for specific hardware (routers, maemo, android), etc. Plus backups of some of those so that they can always be reverted.
Sorry for the long post, just thought to share in this wonder of technology