As GW says, the techs are not infallible and the software can be wrong - although in my experience, not too often. They are exceptional training aids; a Level D device with all the bells and whistles particularly. Any level of approved device will make a helicopter pilot better than without sim time for sure, as long as the training is carried out well and the device is used within its limitations.
Watch out for the visuals close to the ground. Collimated displays have limitations whatever the field of view. And if you experience something different in the real aircraft to the sim let it be known so the software can be changed and others can learn from your experience. I have come across the "that cannot be right" by people accepting simulators only to find out that they were making an assumption based on an older sim they had worked with, so do not believe everything is correct. On the other hand and without better information to go on obey the number one rule of IF - trust the instruments!