A couple of things. First, you made a good move by taking the BD bike to a shop and having it tuned. I recently bought one of their bikes, and it had no grease in the headset bearings, front and rear hub, or bottom bracket threads (sealed unit). You could have ridden the bike as it was out of the box (with some problems-- the headset was way over tight) but it would have been disaster down the road.
Second, BD shaves price points off with some very cheap components. To be fair, this is also a problem with a lot of LBS bikes (as is poor assembly, in particular of the lower end models). This means many of the parts will be replaced, in some cases rather quickly if you actually ride the bike.
BD tends to make cheaper versions of bikes they know will be popular. They're a fairly market savvy batch, although I think they may have jumped the gun a bit on the model I bought. Here, for instance is mine as purchased:
as it is now:
I don't doubt they hack other companies designs to some extent-- almost no bike companies are really innovators-- and it wouldn't surprise me at all if the bikes are sourced from some of the same factories. We live in a world where branding is very very important, which is at least part of the reason BD bought up old respected names like Mercier. Linus? I dunno, you'd have to ask. But I'm sure BD noted a market for Dutch style city bikes growing in the US, and moved to take advantage.
The build quality is nothing special, but it isn't on most LBS bikes I see, either. We're not talking Waterford here or anything...