I think they do come mostly assembled, but its a good idea to check torque on all of the components and tune them up good.

The first major bike work I EVER did was taking my old mongoose mountain bike down to a bare frame and putting on about $500 in parts I had ordered. It was a lot easier than I thought it would be, that's for sure. I didn't rush it, and I think it took me a few hours. Never had a problem with that bike, either. Anyone who puts their mind to it, has the proper tools, and some mechanical ability should have no problems with bikes from bikesdirect.

However, if you don't have the tools, mechanical ability, or time...go to a bike shop and spend more. Someone with the tools and knowledge can get pretty good deals though...