ruler gripper
 

Has anyone used this product? Is it worth buying? I am hoping it will help me avoid rotary cutting my fingers.

If you mean the suction cup handle thingy then yes, I did get one of these when I started quilting but I got a klutz glove as well because well, I am a klutz.
I found the handle a bit awkward and I had a hard time keeping the long ruler from shifting on the fabric. The suction cups hold fine but you can't keep pressure along the length of the ruler. I never cut my fingers though.
I liked the klutz glove much better, https://www.quiltingcompany.com/store/klutz-glove-med . it has grip dots on the hand so that it holds the ruler and you can walk your fingers along the length of the ruler so you don't get shifting.
Safe quilting.

I have had the suction cup one for several years. Used it twice. Now it is in the garage sale box. We are downsizing and I am going through stuff i never use and getting rid of it.

I have one of those, and for me it was a waste of money. Worked for a while, but then I couldn't get it to stay down after I attached it. So it is now in the "need to get rid of" stuff.

I use grip strips on my rulers. They work great for me. No more finger walking up the ruler as I cut long pieces. They are available almost everywhere.

I won't cut without a safety tool. I have the large Gypsy Gripper and it's better then nothing for safety and I will use it if that is all available. I like the small round one though for odd shape rulers and templates. The best I've found is the Quilter's Slidelock. It's great. I also use the cut resistant glove when I'm at a class or workshop.

It works ok but the large suction cups cover up a lot of the lines making it more difficult to measure.

I don't like mine at all. It's way too big and covers up lines I need to use. For me a total waste of money.

Get a slide lock ruler

Slidelock rulers are one of the best purchases I ever made:
https://www.quiltersslidelock.com/slidelock-models/

I use the Slidelocks both to cut with, and just to place on top of other rulers before cutting. They help enormously with slippage and keep my ruler hand high and out of the way of the cutter.

If you can't afford the Slidelocks, the best ruler grips I tried (and I tried about half a dozen different types) are the grip strips: https://www.amazon.com/Guidelines4qu...dp/B009DF9DLA/
I have even used them under one of my June Tailor Shape Cut mats.

You do not need grip strips if you get Slidelocks.