The idea is that bidding early shows to other potential bidders that there is value in the item. The problem to the theory is Spoo's auctions are already followed by a lot of clothing aficionados who know what an item is worth. In this particular case there were already 8 or 9 bids when I placed my bid this afternoon. I bid $45, the winning bid was almost twice that.
Obviously, the situation will differ depending upon the item.
However, in general, if you bid early, you indicate to others that you value an item and you indicate the value that the item has to you (your max bid amount). Some (thankfully not all) people will try to establish your max bid amount by placing incremental bid after incremental bid so as to find out what the current max bid amount is. This pushes up the price. Unfortunately, given human psychology, people are affected by what other people will pay for an item - it's well established that if an item is more expensive, a reasonable percentage of people will actually perceive it as being more desirable. The auction structure also inspires our competitive spirit - people want to win and so they bid more.
Therefore, bidding early - even though you may decide to simply bid your max amount and then bow out without bidding further at all - can influence the bidding behaviour of others. It can push up the price so that the max bid amount is higher than your max bid amount.
Now, it may well be that the bid that won the item was always going to be higher than your max bid, but it's also the case that by putting in your max bid early, you can drive up the price as other buyers strive to beat your max bid and that can then push up the amount that other people bid for the item. If you snipe, though, it means that other people don't have a chance to find out your bid and react to it and so they may, therefore, not bid as much as they may otherwise have bid had they known that your bid was $X.
TL/DR - I still think that it's best to snipe at the last minute as I think that it tends to keep prices down and keeps other people from knowing about your max bid amount.