Hi Pam, I have a Go cutter with the hand crank. Turning the crank is a lot of work so with your back problems, you don't want a hand crank.
Initially I used my Go cutter to cut millions of 5" squares for the I Spy quilt sets I sell. It was good for that but the die wore out quickly. I got it replaced and the replacement is going dull even faster than the original one. Plus you have to keep buying mats, as the cutter cuts them up pretty bad, and then you no longer get good cuts. For these reasons, I hardly use my Go cutter anymore.
You have a little different situation with your back problem, so you may need a cutter. But my general feeling about them is that they are a lot of money for a little convenience. I'd rather cut with my rotary and rulers.