Home grown runners are magic, not tough and stringy at all if you get a decent variety (I like White Lady) - they don't like hanging around so shop bought ones are always inferior. Preparation for eating or freezing easy too, just need chopping into chunks and home ones are lovely and tender, no need for stringing or bean slicers.
I like French too, especially Cobra and Borlotti but runners need defending as they're a brilliant crop in British climate for home growers.