I guess the success you have with this pin stop really depends on the type of floor you use it with.
For me, it's quite hopeless on tiles, works a bit better on wooden floors.
After experimenting with this for a while I think I'll go back to the pin stops that attach to the chair. I just feel I can't trust this one.
I will however keep it as a backup in my case. The small size makes it super portable and that's a definite plus.