If you're talking about an engine failure in cruise flight, I'll take a helicopter every time. You don't need hundreds of feet of ground run for the landing, you can put it down in any open area with little or no ground run. IMO an engine failure in a helicopter is orders of magnitude safer than in a fixed-wing, and much more likely to result in no injuries. Anything is possible, of course, and you can put the aircraft into situations that are unrecoverable in the event of engine failure, just as you can put an automobile into situations that are unrecoverable in the event of engine failure. But in the general case of cruise flight, regardless of altitude, a helicopter is far more likely to be able to do a safe landing, regardless of what is under it, because of the far lower speed necessary. The rate of descent is not harrowing. It is somewhat higher than most fixed-wing, but it's completely controllable, and the touchdown rate of descent is close to nil.