I've have my bike for almost two months now. The bike (Windsor - The Hour) was simple to put together and seems well made. Only the simple stuff (pedals, handlebars, etc.) needs to be assembled on the frame. All the geartrain components are already taken care of. The wheels have gone slightly out of true pretty quickly and the spokes could have been tighter in the first instance, but nothing a spoke tool can't fix.
I've had several roadbikes/single-speed bikes in carbon, steel, and aluminium, and bought this one since I moved to a new place and wasn't able to bring over my old ones. It's slightly heavier than my last steel frame single speed (a masi), but is a comfy ride and is nimble enough. Great for around the town and speeding past typical mountain/commuter bikes, but of course any proper geared alloy/carbon roadbike or a more aggressive track bike is going to be quicker. The components are also pretty solid considering what I paid for it.
There was an issue with a defective freewheel that constantly made noise in my initial delivery, but I emailed their customer service and their representative (Larry) was very helpful and quickly sent over a proper shimano replacement. I've recommended bikesdirect to friends who are looking for new, inexpensive and bikes.