I have had mine for about 3 months now. It's great for security, but a pain in the backside as I need to take the damn thing to work with me if I want to log onto my bank account whilst I am at work.
The Pin Sentry machines are not unique to the individual and you can use another persons machine to log onto your own account.
As Chris has already mentioned, you jus put your card into the machine and press the 'identify' button, and an 8 digit code will appear on the screen. Enter thos code into the relevant field on the website, and hey presto, you have access to your online account.