Bidding using one of these "Bots" isn't just about outbidding someone for a particular item, Sometimes you have multiple actions going off at the same time and it just isn't possible to bid on them all at once. I have found most times they save you money...I rarely if ever bid on an item until the very end, there are alot of sellers who have people to bid on their Item to see what the bidder is willing to pay (Even at the risk of losing a sale).
Also in the Olds post someone mentioned that it ended in the middle of the night and their would be alot of cranky people the next day, Not when you use a bot, place your bid and sleep like a baby!
There is a few sites that have free versions that you can try out. I use
Bid Sniper by Amherst and good luck!