I've just always wondered if it /actually/ works

If you mean counting cards then yes, it is a statistical certainty that you will come out ahead. It moves the odds from a couple of percent in favour of the house (in the case of perfect basic strategy play) to a couple of percent in your favour. That is, assuming you can find a table that deals deep enough, which isn't likely to happen on the strip.

It's not easy to count and avoid detection though. I'm strictly a basic strategy player, which I guess means I'm a mug!

Rob