The lowest end models are junk,the high end ones are nice. Had one of the ti cross bikes,was my favorite until it was stolen.

Note that bikesdirect is descriptive;you get the bike straight from the manufacturer just like a shop would. Everything needs final adjustment,including the wheels which will need to be tensioned and trued. If you know how to work on bikes,they're a good buy. If not,make sure a decent shop puts it together for you. Also note that unlike a bike shop bike,you must deal with shipment issues. If the bike arrives damaged,you'll have to suss out the issues with the carrier. Also BD won't cover a derailleur hanger damaged in shipment,you'll need to buy a new one.

Basically,they're like anything else on eBay.