As is often the case, I have to disagree with my brethren (and sisteren).
Yes, *theoretically* an autorotational landing following complete power failure is *safer* in a helicopter than is an off-airport landing in an aircraft with complete power failure. However...
...what helicopter pilots tend to gloss over is the great degree of pilot proficiency to pull off a "successful" autorotation. That is, if everything isn't done just right from 50 feet or so to touchdown, severe damage to the aircraft, or even injury to the occupants, is quite likely. This demands a great deal of practice. The problem is, we don't get much practice. Sometimes, none. How many turbine pilots get to do touchdown autorotations with a frequency that is even slightly likely to produce and retain proficiency? How many pilots flying have *never* done a touchdown autorotation in the type(s) they're current in? I rest my case.
Having flown both helicopters and multi-engine airplanes professionally, I can assure you that handling an engine failure on takeoff in a twin requires much less finesse and pilot technique than a touchdown autorotation. Yet, as a twin turbine airplane pilot, I had annual simulator training in the former, while the last time I did an actual touchdown autorotation in a helicopter was some 18 years ago...courtesy of the military.
Undoubtedly the civilian pilots most likely to have a "successful" touchdown autorotation outcome are the folks who are active CFI's. But their level of proficiency will, ironically, also start to decay as they move out of instructing and into larger and turbine-powered equipment. Helicopter simulators are few and far between, and few if any operators do touchdown autorotation training, even in initial qualification; it's just to risky.
The fact that the training is looked on as risky gives you a fair idea of the likelihood of "success" when a real total power failure comes along.
Also conveniently ignored is the tremendous degree of complication to a "successful" autorotation stemming from the lack of availability of a clear, level, and smooth emergency landing site. Quite a high percentage of the time, we fly over trees, slopes, marshy ground, etc., etc. Touchdown on one or more of these types of "surfaces" is again, quite likely to result in severe damage or injury.
In conclusion, far be it from me to come across as a prophet of doom, however I submit that most helicopter pilots greatly overestimate their skill and proficiency, and greatly underestimate the dangers and difficulties involved, in performing touchdown autorotations without damage to the aircraft or injury to the occupants, or to folks or property on the ground. Yes, an airplane off-airport landing involves more terminal energy, however the skill set involved is much less than that required in a helicopter touchdown autorotation; my gut feeling is that you have about equal chance of walking away from either.