Hey! Generally speaking, they are all pretty much garbage. The reason why I say that is because most of these websites require a "Reserve Price" which means the bank isn't willing to sell it lower than that price. If you go to the live auctions in court, they are called "Upset Value".
Now the problem with online bidding is similar to gambling slot machines; there is an algorithm that balances the win/lose ratio (or so we think). Fact of the matter is, we have NO idea how the algorithm works, we just put our money in, spin the dial and pray we win.
Having said that, when bidding online, there is no ability to verify conflict of interest. Meaning, anyone can sign up and bid the property up in price (even the seller who owns the property). Therefore, what seems to be a good deal (starting bid), will likely get blown out of the water because the bank doesn't want to lose (or wants to lose as little). To add insult to injury, you can win the bid BUT, the seller still retains the ability to deny your winning bid.
Long story short, in my humble opinion, it is a waste of time.