Robinson, greatest Umm?
The 22/44 and no doubt the 66 are good helicopters in their own right but they do have limitations just like any other helicopter. I don't think you could compare a AS350 or even Enstrom with a 66. They are totally different machines.
Unfortunately those that think the robinsons go for 2200 hrs without anything going wrong are mistaken. They still go through the usual consumables like pitch links, fuel pumps, regulators etc.
As for the greatest, well, I agree they have done a good job getting the average joe into flying helicopters and continue to do so but you could say that Bell is the greatest for building the Huey which saved so many lives in the Vietnam war, many of which are still in service today. Why not stop there, how about Sikorsky S61/Westland Seaking for the SAR efforts or the Scout/Wasp for their efforts during the Falklands?
You see how 'greatest' can be hard to attribute.