As I mentioned to you before, these kinds of online dealers usually wildly understate the amount of skilled assembly needed to be comparable to a bike purchased at a good local dealer, in addition to the value a shop provides in fitting, warranty support, and usually some bundled service. With this taken into account the bike may still be a good deal, but this is the case more often at the high end than at the low end. Some exceptions are companies like Canyon and, in my experience, to a somewhat lesser degree Diamondback that do more legitimate preassembly. Bikesonline claims to be more this business model--I haven't seen any of their bikes so I can't comment. If so, that'd be a decent deal. There are still meaningful value additions from a local dealer, but only you can ultimately weigh them.
I work at a local bicycle shop, so I have a somewhat biased perspective, but I mostly just want people to have a more complete view of what different options ultimately offer. Consumer direct makes a lot of sense a lot of the time.