First off, I agree with most of the price comments here. You CAN save hundreds but the reason you do is that these bikes are drop shipped from overseas. They are nowhere near ready to ride out of the box. If you are already spending hundreds but also saving hundreds, why not spend the $50-100 that your LBS will charge to build the bike right? For the under $300 fixies and coffee bikes? Maybe not, but you are talking about top of the line and very high end components on these bikes that require fine tuning. If you don't know how, disregard that video on the website site about assembly and go to your LBS. Don't be ashamed, tell them you have a boxed bike that needs building and tuning and if they give you crap about buying online tell them that this bike came out of the same (or better) overseas factory that their Treks, Giants, and Specialized did. You just saved several hundred bucks. The best case is that you develop a rapport with your LBS and they help you down the road. Personally, I am a Performance Buyers Club member and all my labor is half off, so building the bike didn't even cost me that much.
Hope this helps.