It's better if you pass out purely from the rope, this will give you a better chance of staying unconscious (dying after 10+ mins) because you know it was the noose did it's job. That said you could still convulse and loosen the noose/stand up as some people have claimed after passing out. If you pass out largely assisted by hyperventilating, there's more of a chance the rope isn't doing as much as it needs to and you'll wake up shortly.