I've had both a Yamaha and a Club Car. I have chronic back problems and would dread every moment I spent on the Yamaha. The ability of the Aluminum Club Car frame to 'soak up' a good deal of the shock from the bumps is worth its weight in gold.
Years ago I used to race bicycles and rode hand built Italian Steel frames exclusively and relentlessly razzed my friends who rode ridiculous looking large tube diameter aluminum frames. I had always heard about the superior shock absorbing quality of the aluminum frames but stuck faithfully to my steel frames. One day I said to a friend who rode the same dimension frame as I did- lets switch bikes for the day, I want to see what this aluminum thing is all about. After that day, I went out and bought an aluminum frame and haven't looked back since.

Hope this personal experience helps!

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