I use a snipe engine for several reasons.
1. I am not always near a computer when an auction is ending, or am busy with a customer at that time, or -- I JUST PLAIN LOST TRACK OF TIME OR FORGOT!! darn$@&^%(*&!^%darn
2. If I place a proxy bid there are always some nibblers that may not want the item but get some perverse joy out of costing ME more or "helping" the seller get more money for it. AS takes care of that in a really good way. AS also keeps me from getting into the auction "I can't let someone beat ME" mentality and I end up being stupid.
3. I use group bids much of the time, usually ending up winning what I want so cheap even I can't believe it, even tho most of the items go for much more than I want to pay.
4. No one can push up the bid to find out my max and then retract. It does not happen often, but it has happened to me.
5. So, in my opinion, AS beats proxy bidding hands down. Saves me money, gets most of my bids in (I set 9 seconds on a weekend and my snipe was to late - my fault, not AS problem) and on some items no one has any idea that I am watching the item or that I even care.
Sooooo AS ids the way to Goooooo