I've had good luck using eSnipe for many years. From a buyer's perspective, there are many good reasons to use sniping services.
You don't want to alert your competition that there is an item in which you are interested, as that will raise the price. You don't want to get into bidding wars, where you are jockeying for top bid constantly during the duration of the auction, raising the price ever higher.
You also want to discourage shill bidders, either affiliated with the seller or not, who have no intention of winning the auction. They only want to drive the price up, either to benefit the seller, or just for amusement value.
Of course from the seller's standpoint (and that of eBay), sniping services are bad, for exactly the same reasons. They want to push the ending prices ever higher.
You don't want to alert your competition that there is an item in which you are interested, as that will raise the price. You don't want to get into bidding wars, where you are jockeying for top bid constantly during the duration of the auction, raising the price ever higher.
You also want to discourage shill bidders, either affiliated with the seller or not, who have no intention of winning the auction. They only want to drive the price up, either to benefit the seller, or just for amusement value.
Of course from the seller's standpoint (and that of eBay), sniping services are bad, for exactly the same reasons. They want to push the ending prices ever higher.