I spent a couple years working on Aircranes and I can say it is a really marvelous machine. The work it could perform was incredible and I was always amazed that it held together. It was not however the smoothest machine in the sky by any means. In order to get the blades into clean air we ran a split track. Every other blade was about 3 inches higher or lower than the preceeding blade while sitting on the ground. When you were picking up a heavy load the track split could get as much as 2 feet! Definately a rough ride. I've never been airsick in my life but riding in the back seat of a crane while logging, looking down between my legs at the load while bouncing around was a recipe for turning green.
Nick mentioned the rotor sytem being close kin to the H-37 Mojave. In fact the blades on the CH-54A (S-64E) were the same as the H-37 with the addition of the BIM indication system. The B model crane (S-64F) had wider chord blades from the CH-53 as well as basically a CH-53 rotor head which was quite a bit different than the E model head. You'll notice when you see an Aircrane on fires all the mechs are running around in coveralls. Thats because they have to grease the rotorhead each post flight which consists of about 140 grease zercs! It's about a 1 hour job to squirt grease in every one and about another 2 hours to wipe up what was slung all over the rest of the machine from flying that day.
I have to say I like staying clean for a living now but I do miss the days on the Aircrane.
Max