My view on this is highly influenced on my experience with sales in the automotive industry....
If it is a pretty new camera with low shutter count, it is worth more than refurb. Say the camera has 10k shutter count. That camera works great and every part of that camera was well taken car of and every part of that camera has 10k on it.
Also, not all used gear has the same value. Too many people look at a camera and see "used" and think, oh its worth half the new value no matter what. Well, what if you had one camera body with 10k shutter count and another of the same model with 75k shutter count. OR one is in mint condition and you can't even tell it's used while the other has a few scratches and signs of wear?
If it is a fairly used camera, then id buy refurb first. If I know the camera is basically brand new, I'd buy used over refurb.
People forget that refurb is used with a couple new parts while the rest is still used. You don't know what was replaced. Some parts could have more wear than others. They aren't always replaced with new parts either, sometimes they are just replaced with other used parts that work. This is very common in the automotive industry as well. You also have no way of knowing how many "miles" are on the rest of the camera.