I like the idea of BD if you're strapped for cash. I also think you're forced to learn to "tune" a new bike, which is easier than tuning a used bike because everything is new (i.e. no rusted or frozen screws). These skills will be valuable. Some good values can be, in theory, had because it "cuts out the middle man." I don't like BD because it cuts out the middle man and takes money out of the local economy. It functions essentially as the Wal-Mart of bikes. However, I do realize that being fiscally responsible is a luxury position to be in, just like buying fresh bread/meat from a local baker/butcher, which is much more expensive than a supermarket.

I usually try to buy everything hand-made in the EU, but sometimes it's not fiscally possible and when that's not the case, I at least try to buy from a local retailer as it keeps the local economy diverse and thriving. Bookstores are a great example, as I try to buy used from a local second-hand shop because even though Amazon is cheaper, I'd rather hit the local second-hand shop (i.e. not a chain store) on a sunny weekend. When I stop buying from the more expensive local place, it will cease to exist as will their local role in the community (Amazon can't read out loud to a bunch of kids on the weekend in multiple languages, for example.)

The real question is what's your financial position?