I don't have any health issues, but I still have a hard time cutting straight with rulers, and I find it very frustrating when the ruler slips. Then I had a mat with slits in it every 1/2 inch, but sometimes the fabric wasn't folded right underneath and I got waves in my cut lines.
Then I got a QuiltCut. I love it. I wouldn't be able to do the quilting I'm doing today without it. One reader said she didn't use the T-bar, but that's the whole beauty of it! I don't use it for angles much, I just turn my blocks and use the lines on the mat to trim angles.
All in all, I say worth every penny!