I've only seen several REO that were left in decent condition. Most are vacant for a couple of years, with different $ problems. And they seem to be beat to hell, or no maintenance.
So, after seeing it beat up how can you use normal comps. When interest rates really went down, REO were selling at non REO prices. But my experience is that the typical REO is not a typical c4 sales. So how much of a depreciation do you take off, especially if needs work. So then to go see, look for the comps, or go back out to take comp photos being FHA, you made minimal pay for your time.
The ones i did after a foreclosure, a realtor was already involved. So, i had a good talk with the realtor who had inspected the property. Would now know the problems and what the listing realtor said the list price should be. Saved me time. Also, there seemed to only be a couple of realtors who handle them. Before it was many realtors. A mort servicing co handling the REO is a different problem.