I have bought a couple of nice pistols on GunsAmerica but none in an auction. I do know to stay with FFL dealers with as many verified sales as possible on there. There are a lot of scams on there from unverified one time posters. Be Careful!
Tuesday I was at the home of a dealer who sells on GunsAmerica. He said he gets emails when someone hits the "Buy It" button. He works a day job so he has to check his emails as often as possible to keep up on who is interested in his many guns for sale.
I've purchased numerous items from Gunbroker,AuctionArms,and GunsAmerica and of the 3, GunsAmerica has been the least enjoyable.Some of the sellers on that site seem to have a "you can wait until I get to it" attitude that I find a little rude.Personally,I wouldn't purchase anything there unless I positively couldn't find it anywhere else.