im pretty sure it is driver related, my toughbook (running XP) is stable as but that said it has eleven billion tuning programs on it, i reckon the USB to serial driver it comes with is conflicting with another one i have installed for the old white datalogit. I use serial for catalogue now as it offers 100% (never ever had a connect issue) reliability.
For those without so many other tuning programs already loaded i reckon it will work fine, i was not willing to delete programs and drivers i use everyday (or al least 2 3 times a week) just to verify a driver conflict as it does not happen with any other interface.
When it did load up it performed flawlessly so for those looking for a cheap interface its a good option.
If you have vista i reckon your gonna struggle with the usb to serial as its a known issue... even the original datalogit usb to serial was unreliable with vista.....best bet xp.