Our dog (probably Cane Corso) is a Molosser and correspondingly large and heavy. We wanted to have a leash that allows a little more run-out, but not as difficult to handle as a towline.
The Flexi leash is because the right choice. The fabric is solid, so that one even in larger dogs should not be afraid that you can tear yourself away, and because of the color and is always clearly visible.
I would decide at any time to purchase one.