I bought my wife's bike from BD; it was fine. BD can offer cheaper prices because 1) no brick and mortar locations, 2) heavy ~unfinished frames with ugly welds (still fully functional), 3) Older components. It comes in a box, all you have to do is assemble a few pieces. It's a piece of cake. Hers was a gravity liberty 1 - it came with an 8 speed sora/microshift group, with a heavy no name tipple crank, sunrace chain and casette, ect... all for ~$400.00. Worth it in my book.

I would advise looking at the measurements very closely; you can't really send them back without paying a $60.00 or so shipping charge. Perhaps if you link to a few of the bikes you are looking at, with your height, weight, cycling inseam, ect.. we can help you out.