http://www.auctionstealer.com/home.cfm gives upto 3 free 10second snipes a week and no need to download softwear. I set up a seperate eBay account for this so if it gets hacked they don't get to my main account and my paypal account.
The advantage of knowing others bidding limits is that you don't both bid up an item to a point where one of you bows out and then the other pays the next incrument. If I am only willing to bid X for an item but someone is willing to bid X+1 it is silly for me to bid up to X if I already know that I will lose by X+1.