I think it all depends on the area you are in, where we bought was an auction area, (one of areas mentioned by Divvy) nearly all properties were up for auction, we went to many auctions but didn't end up buying that way because we missed out at two and then found somewhere as a private sale, it was only a private sale because no estate agents were involved, if they were would have definitely gone to auction. Here it certainly doesn't seem like people get less because they go for an auction, one of the places we were going for went for 100,000 over the advertised range, and was because it was an auction - two parties really wanted it and pushed it up. I would research what is normal practice in your area, what similar properties are going for at auction, how many are sold prior, how many are passed in etc. Domain has auction results, but I don't think does for Perth. If auction is a rare thing in your area I personally wouldn't go for it, but if is common I wouldn't be scared of it either.