Ah, we've been throught this before.
Many helicopter pilots like the loose, zero-feedback, "wet-noodle" feel of hydraulically assisted cyclics. They feel that any sort of friction at all detracts from their ability to control the ship smoothly, and that "no friction" allows them to make those necessary imperceptible control movements, especially in the hover. Maybe so.
But as the original poster declared, flying in rough air (yes, even hovering in rough air) can cause inintended cyclic movements, no matter how hard you try to prevent them. Think of it this way: *ANY* movement of the cyclic moves the swashplate a commensurate amount. If you move the cyclic 1/8th of an inch, the swashplate moves. Can 1/8th of an inch cause a diversion from "in-trim" flight? Of course!
Now, think of the pilots you know who use no friction at all. If you look at the cyclic in the hands of such pilots, it is almost constantly moving. Oh, the movements may be tiny, but it *is* moving, more than would appear to be "necessary." See it for yourself next time you fly!
My personal belief is that these tiny, unnecessary, unintended movements of the cyclic cause the overall ride quality to deteriorate. Pilots will argue this vehemently. All I can say is that I've spent a lot of time flying with other pilots over my 31-year career, and this is my observation. Personally, I use "some" friction on the cyclic where it is available.
Now, nobody in their right mind would suggest locking a flight control when the aircraft is in the air, or even applying so much friction that movement of the control is impeded. That would be lunacy. So I use just enough friction to give the stick some "break-out force" and drag. I use enough to keep the cyclic from moving if I loosen my grip or release it. I use it to dampen out unintended movements. Experimentation helps.
As an airplane pilot too, I know that flying an airplane with zero friction on the controls would be a difficult, fatiguing experience. (Try flying a simulator with no springs or any kind of dampening device on the primary control stick/wheel.) Why we helicopter pilots elect to do so when there is an alternative is beyond me. I've never understood it. But every pilot is different; to each his/her own.
My advice: If cyclic friction is available, use it.