I've always be tempted though never did in the end.
I have been to an auction before though, and if you are going to bid, you need to do a lot of research on the property BEFORE the auction, and set yourself a maximum price, and then have the discipline not to break your maximum price in the heat of the action.
It's very easy to end up paying more than you wished for.
That said, with a bit of luck you can pick up bargains.
I also watched a TV documentary once about this and the best bargains are when the property advertised is far from the place of the auction, say 100 miles or so. In such scenario, few people would have made the effort of doing the homework, so few would bid, and you can pick p a bargain.