I tend to favor the regular bidding for stuff, as seems to work out better and seems to get higher prices, but on the flip side everything that I have listed on BIN/BO has sold normally I try to get a BO, where they skip the paypal or ebay fees and save some cash all round, thats the nice thing with BO, you can send an offer and an explanation of why etc, for a machine I would say probably BIN/BO is the best route, whereas parts I would still opt for the regular auction style.