Never flown one, but I have actually seen one in person. Refuelled a logger in Wyoming a few years ago, and watched him start up and fly away afterwards. While he was sitting on the ground with engine idling, the vibration was so bad that his head was bouncing around like a bobble-head doll. Not my idea of a good time. Hope it got better in flight. Correction, it had to get better in flight; no one could possibly withstand what I saw for any length of time.