Usually GOOG had best results for technical queries --but fresh results for those tend to be the better results (things go out of date pretty quick because of quicker release cycles)
However, on occasion it has been difficult to find very specific results to non technical questions --I never even bothered with DDG or Bing, but now I will surely give them a try.
If they are data driven (and they are) for their average users, long tail, old results probably don't make sense --how many people really go down to page 20 of the SERP? I'm sure it's a very miniscule number.