Having owned both I have to agree that the A is a little more roomier with the higher cab area and better view.
My Class A was the same length as my current Class C, but the Class C seems easier to park and maneuver.
BUT an A is way more expensive to maintain as is the cost of tires and service. It is higher and as such it is harder to get into and out of. My current Class C has more storage room than my old Class A. As the newer Class Cs seem to have now.
If Age and health are a factor my choice would be the C.It is easier to get into and out of, it is easier to drive than my Class A ever was and it is it is more comfortable all around. In short it suites my needs.
I would suggest you find what suites your needs and you are comfortable driving and can afford maintaining.