If you consider the BIN to be an attractive price, go for it. I see too many people skip BINs and instead get into bidding on an item that ultimately goes for more.

+1 If it is a hard to find part, and you consider the BIN price to be OK, I would go with the BIN as well. Waiting on an auction that may go for less, could go for more, is too risky. Now if it is a common item that shows up all of the time, I look for the one with a poorly written ad, lousy title, description, bad pics, etc., and try to get a deal.

I've had various buying strategies for ebay. Recently, I met a guy who just looks at newly posted BINs and clicks on them fast. Every month or two, he spots a bike at a well below market BIN, and swoops in. Some of his buys have been incredible. He typically makes at least 2X the price on a part out, if not more.