I bought a used bike for my wife on-line. No problems with the bike, problem with the wife who told me that after trying it, she really really didn't like drop bars, so the price went up 50% to get my LBS to adapt flat bars.
My custom Bilenky was perfect straight out of the box. Aside from sporadic problems repacking the S&S coupled bike to get it back into its shipping case (user error in each event), I've had no problems. Fit, function, ride, shifting -- all were perfectly dialed in. Literally the first problem I had with the bike was when I put it together a couple hundred miles from home for an "away" century and found the rear tire was bald after a few thousand miles. I chickened slightly and rode the metric the next day.