I have a Selway, a Thunderhorn, and a Saunders recurve bow stringer.
They all work pretty well, but if I had to choose one, it would probably be the Saunders. It is small, so it fits in my possibles bag in a zip lock bag. The upper limb gripper is the best of the three. It is three sided, softer material, and absolutely won't slip.
Still, any of the three are safe alternatives to not using a stringer. You can find LOTS of old recurves with twisted limbs from the old step-through stringing method most of us old-timers grew up with. Heck, I didn't even know there was such a thing as a bow stringer when I started shooting back in the '60s!