[swarmee]

Yeah, odd post from the OP. There are a bunch of reasons for and against using a sniping service.
Pros: Auction can close at 4am and you can still bid with seconds to go while you're sleeping.
Single bid at the end *reduces* the likelihood of being raised either by the consignor/owner or other bidders. Many only bid when they get the email from eBay saying "You're no longer the high bidder..."
If you get stressed out watching the end of auctions, it can reduce your blood pressure.

Cons: Sometimes snipes don't go through because eBay turns on their Captcha software to root out bots from bidding, and sniping services are by definition, bots. (Strong passwords can reduce the odds of your getting the captcha block, but this mainly seems to happen on Sunday nights which is when a lot of big cards get sold.)
You have to remember to change your password in the sniping service whenever you change it on eBay, or else they won't go through.
Some sniping services have had their own network outages and didn't make bids.

I have never signed up for one, since I prefer to watch the end of auctions, and if it's important enough, I'll even wake up in the middle of the night to bid. Bidding your max hours before the end time is just costing you more money.