The problem with last second bidding is that you have to get it right.
You also have to take a chance that you won't suffer a temporary outage on your internet connection during those last few seconds. Using a sniping tool or staring at your computer screen with your finger hovering over the button could be futile if a BT engineer decides to do some maintenance work just as the clock counts down. Service interruptions happen, and by the time your internet connection has re-established itself, it might be too late for your last minute snipe to count.
I won't chase listings and bid up the price to silly levels anyway. Most of what I bid on is not rare and exotic, and often attracts little interest from others, so the bid early and see what happens method works OK for me. I decide what I'm willing to pay and stick that number in the box. If it's something nice and I've got the time, I might watch the end of the auction, and I might increase my bid by a couple of quid if I think it looks a bit dodgy judging by how many other bids have been made. Most of the time though, I'm not going to cry over not winning an auction so I just bid once and wait for it to end.