Worst experience I've had w/ a part from Ebay was a door handle that, although the fit isn't quite perfect (hard to tell) and it tends to stick, it still works fine and gets the job done. That's the worst, most have been much better, including the door handle for the other side of the car, from the same vendor.
If it's a powerseller or Ebay store w/ a good reputation, should be fine.